Foto personale

Pagina personale di Maria Giovanna VEZZALINI

Dipartimento di Scienze Chimiche e Geologiche
Dipartimento di Scienze Chimiche e Geologiche - Sede Dipartimento di Scienze Chimiche e Geologiche

Rossella Arletti; Ettore Fois; Lara Gigli; Giovanna Vezzalini; Simona Quartieri; Gloria Tabacchi ( 2017 ) - Irreversible Conversion of a Water-Ethanol Solution into an Organized Two-Dimensional Network of Alternating Supramolecular Units in a Hydrophobic Zeolite under Pressure - ANGEWANDTE CHEMIE. INTERNATIONAL EDITION - n. volume 56 - pp. da 2105 a 2109 ISSN: 1433-7851 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Turning disorder into organization is a key issue in science. By making use of X-ray powder diffraction and modeling studies, we show herein that high pressures in combination with the shape and space constraints of the hydrophobic all-silica zeolite ferrierite separate an ethanol-water liquid mixture into ethanol dimer wires and water tetramer squares. The confined supramolecular blocks alternate in a binary two-dimensional (2D) architecture that remains stable upon complete pressure release. These results support the combined use of high pressures and porous networks as a viable strategy for driving the organization of molecules or nano-objects towards complex, pre-defined patterns relevant for the realization of novel functional nanocomposites.

Arletti, Rossella; Giacobbe, Carlotta; Quartieri, Simona; Vezzalini, Giovanna . ( 2017 ) - The Influence of the Framework and Extraframework Content on the High Pressure Behavior of the GIS Type Zeolites: The Case of Amicite. - MINERALS - n. volume 7 - pp. da 18 a 35 ISSN: 2075-163X [Articolo in rivista (262) - Articolo su rivista]
Abstract

This paper reports a study, performed by in-situ synchrotron X-ray Powder Diffraction, of the high pressure behavior of the natural zeolite amicite [K4 Na4 (Al8 Si8 O32 )·10H2 O], the GIS-type phase with ordered (Si, Al) and (Na, K) distribution. The experiments were carried out up to 8.13(5) GPa in methanol:ethanol:water = 16:3:1 (m.e.w.) and 8.68(5) GPa in silicone oil (s.o.). The crystal structure refinements of the patterns collected in m.e.w. were performed up to 4.71(5) GPa, while for the patterns collected in s.o. only the unit cell parameters were determined as a function of pressure. The observed framework deformation mechanism—similar to that reported for the other studied phases with GIS topology—is essentially driven by the distortion of the “double crankshaft” chains and the consequent changed shape of the 8-ring channels. The pressure-induced over-hydration observed in the experiment performed in aqueous medium occurs without unit cell volume expansion, and is substantially reversible. A comparison is made with the high pressure behavior of the other GIS-type phases, and the strong influence on compressibility of the chemical composition of both framework and extraframework species is discussed.

Cannavò, Valentina; Cardarelli, Andrea; Levi, Sara Tiziana; Lugli, Stefano; Vezzalini, Giovanna ( 2016 ) - Fabrics and archaeological facies in northern Italy: an integrated approach to technological and stylistic choices of Bronze Age pottery production - JOURNAL OF ARCHAEOLOGICAL SCIENCE: REPORTS - pp. da 1 a 10 ISSN: 2352-409X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The pottery production is a well-attested tradition in northern and central Italy during Middle and Recent Bronze Age (17-12 cent. B.C.). This paper presents for the first time a synthesis of the archaeometrical data in order to characterize the pottery production. Petrographic, mineralogical (XRPD) and chemical analyses (XRF) are considered from Emilia, Romagna, southern Veneto and northern Tuscany, 400 pots from 21 sites have been analysed. Starting from Emilia, characterized by the Terramare facies, this work moved to the surrounding areas, defining 20 Fabric Units based on temper composition and the general production trends. Raw materials used for the paste preparation clearly reflects the different geological and cultural contexts and are coherent with the hypothesis of a local production. Otherwise, some cases of circulation of products, styles and craftsmen are recognized in the Po valley and Tuscany. The results of this investigation indicate that the archaeological facies in northern Italy during the central phases of the Bronze Age are different also in terms of technological choices and traditions and not only stylistically.

Arletti, Rossella; Ronchi, Laura; Quartieri,Simona; Vezzalini, Giovanna; Ryzhikov, Andrey; Nouali, Habiba; Daou, T. Jean; Patarin, Joel ( 2016 ) - Intrusion-Extrusion Experiments of MgCl2 Aqueous Solution in Pure Silica Ferrierite: Evidence of the Nature of Intruded Liquid by in Situ High Pressure Synchrotron X-Ray Powder Diffraction. - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 235 - pp. da 253 a 260 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Experimental intrusion-extrusion isotherms of MgCl221H2O solution were recorded at room temperature on pure silica FER-type zeolite (Si-FER). The intrusion occurs at 195 MPa and the phenomenon is completely reversible with a slight hysteresis. The “Si-FER - MgCl2 aqueous solution” system behaves like a spring. The material was deeply characterized before and after intrusion-extrusion experiments and no significant changes were observed. The unit cell parameters were refined e on the basis of the in situ synchrotron X-ray powder diffraction data - up to 1.47 GPa and then at Pamb upon pressure release. The Rietveld refinement of the data collected at 0.28 GPa (280 MPa), a pressure close to the intrusion value, shows that both ions and water molecules present in the MgCl2 aqueous solution were intruded in the porosities. However, the solvation degree of the intruded ions differs from the initial solution, revealing a partial desolvation of both magnesium and chloride ions. As a whole, the nature and amount of the intruded species correspond to a MgCl210H2O composition. Moreover, at a higher pressure (0.68 GPa), a phase transition from the orthorhombic Pmnn to the monoclinic P21/n s.g. is observed in Si-FER. At 1.47 GPa, the zeolite maintains this monoclinic symmetry, while another phase transition, to the monoclinic P21 s g., is argued from the analysis of the pattern of the sample compressed to 2.6 GPa and then collected upon pressure release to ambient conditions.

Lotti, Paolo; Arletti, Rossella; Gatta, G. Diego; Quartieri, Simona; Vezzalini, Giovanna; Merlini, Marco; Dmitriev, Vladimir; Hanfland, Michael ( 2015 ) - Compressibility and crystal- fluid interactions in all-silica ferrierite at high pressure - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 218 - pp. da 42 a 54 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The high-pressure behavior of a synthetic siliceous ferrierite has been studied by in situ single-crystal and powder synchrotron X-ray diffraction with a diamond anvil cell, using four different P-transmitting fluids: the non-penetrating silicone oil and the potentially pore-penetrating methanol:ethanol:H2O ¼ 16:3:1 mixture, ethylene glycol and 2methyl-2propen-1ol. The high-pressure experiment in silicone oil shows a remarkable flexibility of the FER framework. Two displacive phase transitions, following the path Pmnn-to-P121/n1-to-P21/n11 with pressure, were observed. The three polymorphs were found to share a virtually identical bulk compressibility, though showing a different anisotropic pattern. The experiments with potentially penetrating media enhanced the occurrence of a complex scenario, from which the P-induced intrusion of fluid molecules into the FER structural voids can be assumed by the different phase-transition paths and compressibility patterns, by the calculated residual electron density and by the different deformation mechanisms at the atomic scale, observed as a function of the used medium. The starting orthorhombic polymorph was always restored upon decompression in all the experiments. The roles of the different surface area in single crystal and polycrystalline samples, and of the process kinetics on the compressibility and crystalefluid interactions, are discussed.

Gigli, Lara; Arletti, Rossella; Vitillo, Jenny G.; Alberto, Gabriele; Martra, Gianmario; Devaux, André; Vezzalini, Giovanna ( 2015 ) - Thionine Dye Confined in Zeolite L: Synthesis Location and Optical Properties - JOURNAL OF PHYSICAL CHEMISTRY. C. - n. volume 119 - pp. da 16156 a 16165 ISSN: 1932-7455 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The process of light conversion is at present deeply investigated to develop more efficient devices for artificial photosynthesis, water splitting, photovoltaic applications, and targeting therapeutic agents. This process is induced by nanostructured functional materials, such as zeolites light sensitized by dye molecules adsorbed into their pores. Here a detailed study of the organization of the cationic dye thionine (Th) inserted into the linear 12MR channels of zeolite L is carried out by XRPD, FT-IR spectroscopy for the determination of the host−guest interactionsand UV−vis absorption and photoluminescence spectroscopies for the investigation of the electronic states of the guest. Two composites with different Th loading (labeled ZL/0.15Th and ZL/0.27Th) were obtained through ion exchange. TGA spectra and IR-ATR spectroscopy clearly indicated penetration of Th molecules into the ZL channels. Rietveld structural refinement showed that Th molecules in both composites are aligned parallel to the 12MR channel axis and located on the mirror planes parallel to the c-axis. Water molecules interact strongly with the dye and form a kind of solvent−matrix tube shaped around the Th molecule, favoring the upright arrangement of the molecules. DR−UV−vis spectra of the ZL/Th composites indicated that Th molecules are hosted in the ZL channels in a monomeric form. Photoluminescence spectroscopy demonstrated that photoluminescent dyes correspond to ca. 5% of the total amount of Th molecules in the zeolite porosities. While most of the photoluminescent Th molecules exhibit a lifetime equivalent to Th in solutions, the complementary fraction of photoluminescent Th exhibit significantly longer lifetimes, resulting from an entrapment in defects of the zeolite structure, inducing strong rotational constraints to the molecules.

Gigli, L.; Arletti, R.; Vitillo, J.G.; Martra, G; Alberto, G.; Tabacchi, G.; Fois, E..; Quartieri, S.; Vezzalini, G. ( 2015 ) - Toward molecular wires confined in zeolite channels for an effective transport of electronic excitation energy. ( Congresso CIS6-AIZ&GIC - - 14 -17 Giugno 2015) ( - 6th Czech-Italian-Spanish Conference on Molecular Sieves and Catalysis ) - pp. da 119 a 119 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Sunlight is the fundamental energy source sustaining life on Earth. Green plants are provided of very sophisticated and highly efficient tools to exploit light, they are able to harvest sunlight and to transport electronic excitation energy by means of a particular “antenna system” to reaction centres (natural photosynthesis). The antenna consists of regular arrangements of chlorophyll molecules held at fixed positions by means of proteins. Light absorbed by any of these molecules is transported - by radiationless energy transfer (FRET) - to reaction centres, providing the energy necessary for the chemical processes to be initiated. A green leaf consists of millions of such well-organized antenna devices. A long-standing challenge has been the development of an artificial system able to mimic the photosynthetic system. Artificial antenna systems can be realized once several organized chromophores are able to absorb the incident light and to channel the excitation energy to a common acceptor component1-3. Artificial antenna can be built by incorporating dyes into the one-dimensional channels of zeolite L (ZL). ZL crystals feature strictly parallel nano sized channels arranged in hexagonal symmetry. These channels can be filled with high concentration of suitable guests. The geometric constraints imposed by the host structure allow achieving supramolecular organization of photoactive guests1. It has been shown2,that the properties of the dye-ZL systems depend on the molecular packing inside the channels, controlling the intermolecular and the dyes/framework interactions In this work we presents a study on the optical properties of a two –dyes antenna system in which fluorenone molecules (donor molecule) and thionine(acceptor molecule) are organized in Zeolite L porosities. To interpret the optical properties of the hybrids a detailed structural study at atomistic level was mandatory. Due to the impossibility of studying from the structural point of view a two –dyes systems, two “one-dye” hybrids (ZL/fluorenone and ZL/thionine) were firstly synthesized and characterized to investigate the intermolecular and the dyes/framework interactions4. The results of thermogravimetric, IR, and X-ray structural refinements carried out for the one-dye system ZL/FL established that 1.5 molecules per unit cell is the maximum FL loading , in contrast with the data reported previously in literature5 and that the FL carbonyl group strong interact with a K+ of the ZL. The FL distribution at maximum loading can be consider as a self-assembly of planar dye molecules into a noncovalent nanoladder. FL molecules organized in such a single, continuous nanostructure of dye molecules did not exhibit significant electronic interactions. Indeed, both absorption (recorded in the diffuse reflectance mode) and photoemission electronic spectra of ZL/FL systems with different FL loading scaled almost linearly in intensity with the amount dye hosted in the unit cell (ranging from 0.5 to 1.5), without significant changes of the spectral profiles. Noticeably, the combination and steady state and time resolved photoluminescence data indicated that even at the maximum loading ca. 90% of FL molecules are photoluminescent, with significant increase in the average quantum yield with respect to FL molecules in solution. Such a finding clearly indicates that excited states coupling (Davydov splitting) is not contributing to the optical properties of the material. The structural study of the ZL/TH system revealed that the maximum possible loading of TH is equal to 0.3 molecules per unit cell in agreement with the TGA and literature data6. Short distances between the carbon, sulfur and nitrogen atoms and two water molecule sites , in turn at bond distance from the oxygen atoms of the main channel, suggested a water-mediated Th-ZL interactions7. Moreover, IR spectroscopy provided evidence of the interaction of

Gigli, L.; Arletti, R.; Vitillo, J.G.; Martra, G; Alberto, G.; Tabacchi, G.; Fois, E.; Quartieri, S.; Vezzalini, G. ( 2015 ) - Molecular wires confined in zeolite L channels for an effective transport of electronic excitation energy: a synchrotron structural study. ( XXIII SILS MEETING - - 8-10 luglio 2015) ( - N/A ) - pp. da 3 a 3 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Sunlight is the fundamental energy source sustaining life on Earth. Green plants are provided of very sophisticated and highly efficient tools to exploit light, they are able to harvest sunlight and to transport electronic excitation energy by means of a particular “antenna system” to reaction centers (natural photosynthesis).The development of an artificial system able to mimic the natural phenomenon has been a long-standing challenge. Artificial antenna systems can be realized once several organized chromophores are able to absorb the incident light and to channel the excitation energy to a common acceptor component [1-3]. The optical properties of the systems depend on the molecular packing inside the channels. Artificial antenna can be built by incorporating suitable guests into the one-dimensional channels of zeolite L (ZL). In this work we present a detailed structural study of two hybrid systems in which dyes (fluorenone and thionine) are encapsulated in zeolite L channels. These two molecules were chosen since it has been demonstrated that a “two –dyes antenna system” - in which fluorenone (FL) (donor molecule) and thionine (Th) (acceptor molecule) are organized in Zeolite L porosities - shows remarkable optical properties. Due to the impossibility of studying, from the structural point of view a “two –dyes systems”, two “one-dye” hybrids (ZL/fluorenone and ZL/thionine) were firstly synthesized and characterized [4]. The results of thermogravimetric, IR, and X-ray structural refinements carried out for the one-dye ZL/FL and ZL/Th systems established that 1.5 molecules of FL and 0.3 molecules of Th per unit cell is the maximum loading, respectively. The FL carbonyl group strong interacts with a K+ of the ZL. On the other hand, short distances between the carbon, sulfur and nitrogen atoms of Th and two water molecule sites, in turn at bond distance from the oxygen atoms of the main channel, suggested a water-mediated Th-ZL interactions. The energy transfer from excited FL molecules, forming the non-covalent nano-ladder in the ZL channel, and Th, deposited on the external surface of ZL particles, is currently under investigation. In conclusion concerning the optical properties of our composites, no evidence of Davydov splitting emerged from our study, indicating that one of the main competitors of the FRET mechanism is not operative notwithstanding the close packed arrangement of FL. We believe that this feature is of overwhelming relevance in view of application of such a system in artificial antenna devices. The authors acknowledge the Italian Ministry of Education, MIUR-Project: “Futuro in Ricerca 2012 - ImPACT- RBFR12CLQD”.

Arletti, R.; Leardini, L.; Vezzalini, M.G. ; Quartieri, S.; Gigli, L.; Santoro, M.; Haines,J. ; Rouquette, J.; Konczewicz, L. ( 2015 ) - Pressure-induced penetration of guest molecules in high-silica zeolites: the case of mordenite - PHYSICAL CHEMISTRY CHEMICAL PHYSICS - n. volume 17 - pp. da 24262 a 24274 ISSN: 1463-9076 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A synthetic high-silica mordenite (HS-MOR) has been compressed in both non-penetrating (silicone oil, s.o.) and penetrating [methanol : ethanol : water (16 : 3 : 1) (m.e.w.), water : ethanol (3 : 1) (w.e.), and ethylene glycol (e.gl.)] pressure transmitting media (PTM). In situ high-pressure (HP) synchrotron X-ray powder diffraction (XRPD) experiments allowed the unit cell parameters to be followed up to 1.6, 1.8, 8.4, and 6.7 GPa in s.o., w.e., m.e.w., and e.gl., respectively. Moreover, e.gl. was also used as a PTM in in situ HP Raman and ex situ IR experiments. The structural refinement of HS-MOR compressed in e.gl. at 0.1 GPa – the lowest investigated pressure – revealed the presence of 3.5 ethylene glycol molecules per unit cell. The infrared spectrum of the recovered sample, after compression to 1 GPa, is consistent with the insertion of ethylene glycol molecules in the pores. XRPD and Raman spectroscopy experiments performed under pressure indicated the insertion of a small number of guest molecules. Ethylene glycol is partially retained inside mordenite upon pressure release. A symmetry lowering was observed in s.o. above 0.8 GPa, while above 1.6 GPa the patterns indicated a rapid loss of long range order. From ambient pressure (Pamb) to 1.6 GPa, a high cell volume contraction (DV = 9.5%) was determined. The patterns collected with penetrating PTM suggested the penetration of guest molecules into the porous host matrix, starting from a very low P regime. The entrapment of PTM molecules inside micropores contributes to the stiffening of the structure and, as a consequence, to the decrease of the compressibility with respect to that measured in s.o. From the structural point of view, HS-MOR reacts to compression and to the penetration of different guest species with appropriate framework deformations. Interestingly, ethylene glycol is partially retained inside mordenite upon pressure release, which is of importance for potential application of this composite material.

Danisi, Rosa Micaela; Armbruster, Thomas; Arletti, Rossella; Gatta, G. Diego; Vezzalini, MariaGiovanna; Quartieri, Simona; Dmitriev, Vladimir ( 2015 ) - Elastic behavior and pressure-induced structural modifications of the microporous Ca(VO)Si4O10 4H2O dimorphs cavansite and pentagonite - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 204 - pp. da 257 a 268 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The behavior of natural microporous cavansite and pentagonite, orthorhombic dimorphs of Ca(VO) (Si4O10) 4H2O, was studied at high pressure by means of in situ synchrotron X-ray powder diffraction with a diamond anvil cell using two different pressure-transmitting fluids: methanol:ethanol: water = 16:3:1 (m.e.w.) and silicone oil (s.o.). In situ diffraction-data on a cavansite sample were collected up to 8.17(5) GPa in m.e.w, and up to 7.28(5) GPa in s.o. The high-pressure structure evolution was studied on the basis of structural refinements at 1.08(5), 3.27(5) and 6.45(5) GPa. The compressional behavior is strongly anisotropic. When the sample is compressed in s.o. from Pamb to 7.28(5) GPa, the volume contraction is 12.2%, whereas a, b and c decrease by 1.6%, 10.3% and 0.3%, respectively. The main deformation mechanisms at high-pressure are basically driven by variation of the T–O–T angles. Powder diffraction data on a pentagonite sample were collected up to 8.26(5) GPa in m.e.w and 8.35(5) GPa in s.o. Additional single-crystal X-ray diffraction experiments were performed in m.e.w. up to 2.04(5) GPa. In both cases, pressure-induced over-hydration was observed in m.e.w. at high pressure. The penetration of a new H2O molecule leads to a stiffening effect of the whole structure. Moreover, between 2.45(5) and 2.96(5) GPa in m.e.w., a phase transition from an orthorhombic to a triclinic phase was observed. In s.o. pentagonite also transformed to a triclinic phase above 1.71(5) GPa. The overall compressibility of pentagonite and cavansite in s.o. is comparable, with a volume contraction of 11.6% and 12.2%, respectively.

Leardini, L.; Quartieri, S.; Vezzalini, G.; Arletti, R. ( 2015 ) - Thermal behaviour of siliceous faujasite: further structural interpretation of negative thermal expansion - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 202 - pp. da 226 a 233 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The high-temperature behaviour of siliceous faujasite (Si-Y) was investigated by in situ synchrotron Xray powder diffraction from room temperature up to 1123 K. This porous phase is remarkably stable when heated, and no phase transitions or changes in symmetry are observed. A marked negative thermal expansion (NTE), already reported in literature for a heating range from 25 to 573 K, was confirmed up to about 923 K. Above this temperature a positive thermal expansion was observed. Si-Y’s thermal behaviour was interpreted on the basis of the transverse thermal vibrations of the oxygen atoms involved in the T–O–T linkages and a series of other structural features characterizing the faujasite structure, namely the T–T distances between adjacent tetrahedral sites, the thickness of the double 6-membered rings, and the ditrigonal index of the 6-membered rings. Moreover, the thermal behaviour of several other anhydrous porous materials with NTE behaviour is discussed and compared to that of Si-Y.

L.De Fe rri; P.P. Lottici; G. Vezzalini ( 2014 ) - Characterization of alteration phases on Potash-Lime-Silica glass - CORROSION SCIENCE - n. volume 80 - pp. da 434 a 441 ISSN: 0010-938X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Glass with Potash–Lime–Silica (PLS) composition was typically produced for the cathedral windows during the Middle Age in Central and Northern Europe and is known to be very sensitive to the attack of the atmospheric pollutants. PLS glass, containing different amounts of K2O (sample V1 = 15 wt%, V2 = 20 wt%, V3 = 25 wt%), was produced and aged in concentrated boiling H2SO4 and in high temperature-high pressure water, to simulate separately the two alteration processes of leaching (ion exchange) and dissolution, respectively. The aged samples were studied by micro-Raman spectroscopy, by XRPD and by SEM–EDS technique to identify the neo-formed crystalline phases, to get deeper insight into degradation and stability of these systems. The behavior of the glasses as revealed by Raman spectroscopy depends on the K2O content. Gypsum (CaSO42H2O), bassanite (CaSO41/2H2O) and anhydrite (CaSO4) are found on the alteration layer of the V2 and V3 leached samples. The water aged V1 and V2 glasses show the Raman features of the phyllosilicates gyrolite (Ca16Si24O60(OH)814H2O) and reyerite (KCa14Si24O60(OH)55H2O) together with hydroxyapatite (Ca5(PO4)3OH). In the alteration layer of the V3 glass, the Raman spectra suggest a mixture of the Ca–K silicate charoite (K5Ca8(Si6O15)2Si2O9(OH)3(H2O)) and hydroxyapatite.

R. Arletti; G. Vezzalini; S. Quartieri; F. Di Renzo; V. Dmitriev ( 2014 ) - Pressure-induced water intrusion in FER-type zeolites and the influence of extraframework species on structural deformations. - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 191 - pp. da 27 a 37 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The response to pressure of a natural ferrierite from Monastir (Sardinia, Italy) (Mon-FER) and of the synthetic all-silica phase (Si-FER) was investigated by means of in situ synchrotron X-ray powder diffraction in the presence of penetrating (methanol:ethanol:water 16:3:1, m.e.w.) and non-penetrating (silicone oil, s.o.) pressure transmitting media (PTM). The following aspects are discussed: (i) the penetration of extra- H2O molecules into the all-silica phase and the related structural aspects involving both framework and extraframework systems; (ii) the influence of the zeolite composition and of the different PTM used in the compression experiments on the overall elastic parameters of the two investigated samples; (iii) the elastic parameters and the unit cell P-induced deformations of the mineral phase; (iv) the reversibility extents of the observed phenomena. Evidence of H2O molecules penetration during compression of Si-FER in m.e.w. was found. The refinement performed at 0.2 GPa enabled location of 15 H2O molecules forming bulk-like and monodimensional H2O clusters. No methanol or ethanol penetration was observed. The results demonstrate that the free volume of the porous material is not the only parameter influencing water condensation since applied pressure is an additional fundamental factor. The bulk modulus value calculated from Pamb to 4.9 GPa for Mon-FER (K0 = 44 GPa, Kp = 0.2) is intermediate between the lowest (about 14 GPa) and the highest (about 72 GPa) values determined to date for zeolites compressed in non-penetrating PTM. The highest P-induced deformations are observed for Si-FER compressed in s.o. In general, higher rigidity for the natural sample was found in both media.

L. de Ferri; A. Lorenzi; P. P. Lottici; A. Montenero; G. Vezzalini ( 2014 ) - Protection of historical glasses by hybrid sol gel coatings. ( STUDY DAYS ON VENETIAN GLASS Approximately 1600’s - - 27 e 28 febbraio e 1° marzo 2013) ( - Study Days on Venetian Glass approximately 1600’s ) - ATTI - ISTITUTO VENETO DI SCIENZE, LETTERE ED ARTI. CLASSE DI SCIENZE FISICHE, MATEMATICHE E NATURALI - n. volume 172 - pp. da 169 a 175 ISSN: 0392-6680 [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

The water-repellent hybrid coatings designed for the protection of exposed historical windows seem matching quite well the requirements for the Conservation of Cultural Heritage field since they do not give reaction by-products or unreacted fractions that could damage the ancient substrate, are transparent and colorless, and chemically and light stable.

Giovanna Vezzalini; Rossella Arletti and Simona Quartieri ( 2014 ) - High-pressure-induced structural changes, amorphization and molecule penetration in MFI microporous materials: a review - ACTA CRYSTALLOGRAPHICA. SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS - n. volume B70 - pp. da 444 a 451 ISSN: 2052-5206 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This is a comparative study on the high-pressure behavior of microporous materials with an MFI framework type (i.e. natural mutinaite, ZSM-5 and the all-silica phase silicalite-1), based on in-situ experiments in which penetrating and nonpenetrating pressure-transmitting media were used. Different pressure-induced phenomena and deformation mechanisms (e.g. pressure-induced over-hydration, pressure-induced amorphization) are discussed. The influence of framework and extra-framework composition and of the presence of silanol defects on the response to the high pressure of MFI-type zeolites is discussed.

L. Gigli; R. Arletti; G. Tabacchi; E. Fois; J. G. Vitillo; G. Martra;G. Agostini; S. Quartieri; G. Vezzalini ( 2014 ) - Close-Packed Dye Molecules in Zeolite Channels Self-Assemble into Supramolecular Nanoladders. - JOURNAL OF PHYSICAL CHEMISTRY. C - n. volume 118 - pp. da 15732 a 15743 ISSN: 1932-7447 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A tough challenge in nanomaterials chemistry is the determination of the structure of multicomponent nanosystems. Dye−zeolite L composites are building blocks of hierarchically organized multifunctional materials for technological applications. Supramolecular organization inside zeolite L nanochannels, which governs electronic properties, is barely understood. This is especially true for confined close-packed dye molecules, a regime not investigated in applications yet and that might have great potential for future development in this field. Here we realize for the first time composites of zeolite L with maximally packed fluorenone molecules and elucidate their structure by integrated multitechnique analyses. By IR spectroscopy, thermogravimetric analysis, and X-ray diffraction, we establish the maximum degree of dye loading obtained (1.5 molecules per unit cell), and by modeling we reveal that at these conditions fluorenone molecules form quasi 1-D supramolecular nanoladders running along the zeolite channels. Spatial and morphological control provided by the nanoporous matrix combined with a complex blend of strong dye−zeolite and weaker dye−dye van der Waals interactions lie at the origin of this unique architecture, which is also stabilized by the hydrogen bond network of coadsorbed water molecules surrounding the dye nanoladder and penetrating between its rungs.

L. de Ferri; P. P. Lottici; A. Lorenzi; A. Montenero; G. Vezzalini ( 2013 ) - Hybrid sol–gel based coatings for the protection of historical window glass - JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY - n. volume 66 - pp. da 253 a 263 ISSN: 0928-0707 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Medieval glass is commonly attacked by atmospheric pollutants conveyed by water, triggering the corrosion process. Current conservation strategies aim to maintain window glass in its original context, and so it is necessary to protect it from further degradation. Sol–gel technology is very effective for the preparation of protective films, using Si-alkoxide precursors chemically similar to the substrate. The present work discusses water-repellent hybrid sol–gel coatings made from tetra-ethyl-ortho-silicate with different quantities of Si-alkoxides, functionalized with various alkyl groups. The coatings were deposited using the dip-coating technique and characterized by UV–VIS and FT-IR spectroscopy. Static and dynamic contact angle measurements showed an overall homogeneity of the coatings and indicated improved water-repellency when functionalized by long alkyl chains. The coatings with best performance in terms of transparency and contact angle, and with the lowest organic content, were selected and applied to medieval-like glass samples. Colorimetric characterization was carried out using a spectrophotometric scanner before and after application of the coatings and no significant color changes were found. The electron microscopy images revealed relatively even, crack-free coatings, especially with higher organic contents. Contact angle and colorimetric measurements were repeated after accelerated ageing by exposure to UV light and an SO2- saturated atmosphere. A significant decrease in the contact angle was observed only for the samples treated at the highest SO2 concentration. The silica-based materials did not give reaction by-products, were water-repellent, compatible with the substrate, colorless, transparent, and stable under exposure to chemicals and light, thereby satisfying the main requirements for the conservation of Cultural Heritage.

D. Malferrari;A. Laurora;M. Brigatti;M. Coltorti;D. D. Giuseppe;B. Faccini;E. Passaglia;M. Vezzalini ( 2013 ) - Open-field experimentation of an innovative and integrated zeolitite cycle: Project definition and material characterization - RENDICONTI LINCEI. SCIENZE FISICHE E NATURALI - n. volume 24 - pp. da 141 a 150 ISSN: 2037-4631 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This study is a part of the European LIFE +2010 Project "ZeoLIFE - Water pollution reduction and water saving using a natural zeolitite cycle". It characterizes the application of Italian zeolite-rich pyroclastic rocks (zeolitites) as soil conditioner. Laboratory experiments will be tested on an experimental field in the Codigoro area, Ferrara district (North-East Italy). The samples investigated are chabazite- and phillipsite-rich and are all collected in quarries from Central Italy: (1) Grosseto area (Sorano and Sovana); (2) Viterbo area (Farnese, Grotte Santo Stefano, Corchiano, Nepi), and (3) Rome area (Riano). All samples are characterized by more than 30 % of zeolite content, together with volcanic glass, feldspars, pyroxenes, and micas. The quantitative mineralogical characterization of soil samples from Codigoro shows variable proportions of quartz, illite, plagioclase, K-feldspar, calcite, dolomite, chlorite, serpentine, kaolinite, gypsum together with an amorphous residual. Collected data confirm that conditioning of soils with selected zeolitite can be extremely promising for a well evident improvement of the soil quality, and contribute to define a standard approach which can surely find a general application well above the boundaries of the selected area for the field test. © 2013 Accademia Nazionale dei Lincei.

R. Arletti; G. Vezzalini; S. Quartieri; F. Cámara; M. Alvaro ( 2013 ) - A new framework topology in the dehydrated form of zeolite levyne. - AMERICAN MINERALOGIST - n. volume 98 - pp. da 2063 a 2074 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

0003-004X/13/1112–2063$05.00/DOI: http://dx.doi.org/10.2138/am.2013.4583 2063 A new framework topology in the dehydrated form of zeolite levyne Rossella Arletti1, Giovanna Vezzalini2, Simona Quartieri3, Fernando Cámara1 and Matteo Alvaro4,* 1Dipartimento di Scienze della Terra, Università di Torino, via Valperga Caluso n. 35, 10125 Torino, Italy 2Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, via Giuseppe Campi, 183, 41125 Modena, Italy 3Dipartimento di Fisica e Scienze della Terra, Università di Messina, Viale F. Stagno D’Alcontres, 31, 98122 Messina, Italy 4Dipartimento di Scienze della Terra e dell’Ambiente, Università degli Studi di Pavia, Italy; and International Research School of Planetary Sciences, Università G. d’Annunzio, Chieti, Italy A bstract The thermoelastic behavior and structural evolution of a natural levyne-Ca [(Ca7.8 Na2.2K1.1)Σ11.1 Al20.0Si34.2O108⋅51.5H2O; R3m; a = 13.377(4) Å, c = 22.870(1) Å, V = 3544.1(3) Å3] were studied by both T-resolved synchrotron X‑ray powder diffraction (SR-XRPD) between room temperature and 800 °C, and by conventional-source high-temperature single-crystal X‑ray diffraction (SC-XRD). Above 230 °C, water loss and reallocation of extraframework cations induce the straining and consequent breaking of T-O-T bridges in the D6R, with resulting migration of tetrahedral cations to new tetrahedral sites. The new tetrahedra share an edge with the previously occupied tetrahedra. This phenomenon gives rise to a new topology, which coexists to about 40%, with the original one. The new framework consists of a sequence of a novel zeolitic cage (described as a 20-hedron formed by fourteen 6mR and six 4mR) and two consecutive cancrinite cages along [0001]. This topology, which is reported in the database of the hypothetical zeolite structures as 166_2_293, belongs to the ABC-6 family and can be described by the following sequence of 6-rings: ABCBCACAB, to be compared with that of levyne AABCCABBC. In the new topology the extraframework cations are distributed over 3 new sites: one at the center of the 6mR ⊥ [0001] shared by the two cancrinite cages, one near the center of the 6mR ⊥ [0001] at the base of the new cage, and a last one in a 6mR window of the new cage. The 8mR bidimensional channel system originally present in levyne is therefore absent in the new topology and hence molecular diffusion is likely to be partially hindered in the dehydrated form. The phase transition is not completely reversible, at least in the short term, as only partial rehydration was demonstrated.

Gigli, L.; Arletti, R.; Quartieri, S.; Vezzalini, G. ( 2013 ) - Fluorenone dye-Zeolite L hybrid: a novel optical material ( Goldschmidt Conference 2013 - - 25-30 August 2013) ( - Goldschmidt Conference 2013 ) (Goldschmidt 2013 Firenze ITA ) - n. volume 1 - pp. da 1168 a 1168 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

A major challenge facing humanity is developing renewable source of energy. Following the biological blueprint of the natural photosynthesis is possible design synthetic systems for converting light into stored energy: the so called artificial antenna systems. The encapsulation of ordered chromophore molecules into one dimensional zeolite channel systems results in host-guest compounds suitable for the development of novel optical materials such as lenses, infrared light-emitting diodes (used in telecommunications) or dye nanostructured materials for optical data storage [1]. X-ray powder diffraction study of zeolite K-L loaded with 0.5, 1, 1.5, 2 fluorenone-dye (FL) molecules per unit cell (ZL/FL hybrid) [2], was carried out to understand the functionality of these host-guest systems from the structural point of view. These data evidenced a significant change of the unit cell parameters due to the embedding of FL into the ZL 12-membered channels. The Rietveld refinements revealed that the maximum loading is 1.5 FL molecules per unit cell. A strong interaction between FL carbonyl group and two extraframework potassium cations is proved by the short bond distances which make this composite very stable.

de Ferri, L.; Lottici, P. P.; Lorenzi, A.; Montenero, A.; Vezzalini, Maria Giovanna ( 2013 ) - Hybrid sol-gel based protective coatings for historical window glasses. ( INTERNATIONAL CONGRESS ON SCIENCE AND TECHNOLOGY FOR THE CONSERVATION OF CULTURAL HERITAGE - - 2–5 OCTOBER 2012) ( - Science and Technology for the Conservation of Cultural Heritage ) (Taylor & Francis Group London GBR ) - n. volume - - pp. da 231 a 234 ISBN: 9781138000094 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Medieval glass is generally attacked by atmospheric pollutants conveyed by water in liquid or vapor form, which activates the corrosion process. Since the conservation strategies are currently addressed to maintain the windows in their original contexts, it is necessary to protect them from further degradation phenomena. We report here on the results of water-repellent hybrid sol-gel coatings obtained by using tetraethyl orthosilicate (TEOS) mixed with different amounts of Si-alkoxides functionalized with alkyl groups. Static contact angle measurements were performed to check the water-repellency of the surfaces. On the basis of the transparency, the contact angle values and the lowest amount of the organic component, three compositions were selected and applied on medieval-like glass samples that were colorimetrically characterized. The silica-based protective materials don’t lead to reaction by-products, are water-repellent, compatible with the glassy substrate, colorless and transparent, hence satisfy the main requirements of the conservation of Cultural Heritage.

Gigli, L.; Arletti, R.; Fois, E.; Martra, G.; Tabacchi, G.; Vitillo, J.G.; Maria, Giovanna Vezzalini; Quartieri, S. ( 2013 ) - “ImPACT” FIRB Futuro in Ricerca: Structural characterization of fluorenone-zeolite L host-guest complex ( XVII National Congress of Catalysis GIC 2013 and XI National Congress of zeolites Science and Technology - - September, 15-18, 2013) ( - Book of Abstracts of the XVII National Congress of Catalysis GIC 2013 and XI National Congress of zeolites Science and Technology ) (- - ITA ) - n. volume 1 - pp. da 53 a 53 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The HP structural investigations of an all-silica ferrierite showed that, in both experiments, the penetration of water and other species is achieved at very low pressure. All the species entering the channels are arranged in chains running in the middle of the channels. The interaction among the extraframework species and the framework oxygen atoms is very weak, probably as a consequence of the hydrophobicity of the framework.

Gigli, L.; Arletti, R.; Fois, E.; Tabacchi, G.; Quartieri, S.; Vezzalini, G.; Agostini, G. Alberto G.; Martra, G.; Vitillo, J. G. ( 2013 ) - Dye Loading influence on performances of Fluorenone/zeoliteL Light Harvester ( XLI Congresso Nazionale di Chimica Fisica - - 23-27 giugno 2013) ( - Atti XLI Congresso Nazionale di Chimica Fisica ) (- Alessandria ITA ) - n. volume 1 - pp. da 143 a 143 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Zeolite L (LTL), is an appealing and excellent host for the supramolecular organization of different kinds of molecules and complexes. However, relatively few experimental structural information is available about the orientation and alignment of the dye molecules in the zeolite pores. Hence, a detailed structural characterization is of great importance for understanding the functionality of these host-guest systems. Between all the possible guests, neutral dye fluorenone (C13H8O) (FL) has received a considerable attention [1,2] because of its ability to form a host-guest complex with LTL, stable if exposed at the atmosphere. Moreover, the fluorescent nature of fluorenone makes this complex interesting as a component of the energy relay system in artificial antennas. Although a detailed structural characterization is still lacking, theoretical studies have shown as the orientation of fluorenone is especially interesting as it is directly related to the light harvesting properties of fluorenone [3]. Moreover, it has shown as the presence of water can influence on the electronic spectra of this host-guest complex and then affect its performances as light harvester [3]. In this study, three different FL/K-LTL materials characterized by an increasing loading of FL have been synthesized by mixing in inert atmosphere the dehydrated K-LTL and FL powder in ratio of 0.5, 1.0, 1.5 and 2.0 molecules/unit cell, and then heating the samples at 120°C in air for 24 h. The vials were maintained under continuous rotation during the heating in order to optimize the contact between the zeolite and the dye. The samples so obtained were characterized by means of X-ray powder diffraction, thermo-gravimetric analysis, IR and UV-vis spectroscopies, fluorescence and nitrogen adsorption. The incorporation of FL into the K-LTL channels was confirmed by a significant change of the unit cell parameters and by drastic decrease in the K-LTL surface area also at low FL loading. The strong interaction between FL carbonyl group and the extraframework potassium cation predicted by theoretical modelling [1] was confirmed by the short bond distances (2.77 Å), evidenced in the Rietveld refined structure, and by the shift of the C=O stretching frequency evidenced in the IR spectra. Such an interaction explains why FL is not displaced by water molecules when FL/K-LTL hybrid is re-exposed to the air [1]. Interestingly, although the UV-vis absorption spectrum was almost unaffected by the FL loading, the corresponding emission spectrum evidenced a strong influence: the optimum FL/K-LTL ratio was then determined in order to optimize the performances of the device as light harvester. The structural information obtained theoretically and from XRD allowed also to explain the loading dependence of the optical properties of the material and to correlate it with the relative orientation of the fluorenone molecules in the zeolite channels.

Arletti, R.; Quartieri, S.; Vezzalini, G. ( 2013 ) - Elastic behavior of all-silica Ferrierite: HP-induced hydration of a “hydrophobic” zeolite ( 17th International Zeolite Conference - - July, 7-12, 2013) ( - Atti del 17th International Zeolite Conference ) (- Moscow RUS ) - n. volume 1 - pp. da 218 a 219 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The HP structural investigations of an all-silica ferrierite showed that, in both experiments, the penetration of water and alcohols is achieved at very low pressure. All the species entering the pores are arranged in chains running along the central axes of the channels. The interactions among the extraframework molecular species and the framework oxygen atoms are very weak, due to the hydrophobicity of the framework walls.

Brigatti, .M.F.; Laurora, A.; Malferrari, D.; Passaglia, E.; Vezzalini, G. ( 2013 ) - Use of zeolitites from Central Italy in an integrated cycle aimed at water and chemical fertilizers saving (ZEOLIFE – LIFE+10ENV/IT/000321) ( 17th International Zeolite Conference - - July, 7-12, 2013) ( - Atti del 17th International Zeolite Conference ) (- Moscow RUS ) - n. volume 1 - pp. da 243 a 244 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Introduction The project “ZEOLIFE - Water pollution reduction and water saving using a natural zeolitite cycle” has been conceived to test an innovative integrated zeolitite application having the aim to reduce the NH4 content in livestock effluents and correct agricultural soils, with improvement of the yield and economization of water for irrigation and fertilizers. This project leads to a reduction of fresh and groundwater pollution and avoids excessive exploitation of the water resource. For further details visit the website www.zeolife.it. The first goal of the project was to carry out a chemical and physical, as well as mineralogical characterization of several zeolitite samples, coming from different quarries located in Central Italy, in order to select the most suitable raw material to be used throughout the entire project. Samples from the following seven localities were analyzed: Sorano (Gr), Sovana (Gr), Farnese (Vt), Grotte Santo Stefano (Vt), Corchiano (Vt), Nepi (Vt), and Riano (Rm). All the mentioned localities are the closest to the experimental field (Codigoro, Ferrara); in each quarry non-marketable material, namely broken blocks or blocks with irregular shape and size, is available. This material represents an already available reserve of zeolitic tuff that best fit the purposes of this project. Besides the technological properties of the raw material, the final choice also took into account factors of environmental (e.g. carbon footprint) and economic (e.g, cost, full and immediate availability) concern. Experimental In order to obtain representative samples from each examined locality, an appropriate procedure was followed by picking out a total amount of 10 kg of raw material from different points of the quarries. The collected material was accurately ground, and repeatedly quartered until obtaining the needed sample amount. Quantitative mineralogical analyses were carried out using the Rietveld method via the General Structure Analysis System (GSAS) software package [1], combined with the Reference Intensity Ratio (RIR) method for the determination of the amorphous phase [2]. Whole rock chemical analysis was carried out on pressed pellets via a wavelength-dispersive X-Ray Fluorescence (XRF). Loss On Ignition (LOI) was determined by sample heating in a oven at 1100°C. CEC determination of exchanged Ca2+, Mg2+, Na+, and K+ cations was achieved via Atomic Absorption Spectrometer (AAS) measurements. Apparent density was determined as the ratio between the mass of ground sample which fills a measuring cup in loose conditions and the volume of the cup. Water retention was determined using a modified Campbell’s methods [3]. Results and discussion As demonstrated by plenty of experimental scientific works (e.g., [4] for a review), chabazite is very effective not only in NH4 uptake from swine manure, but also in successive controlled NH4 release in soils. Other zeolite species, such as phillipsite, have great potential for 244 NH4 adsorption and retention, but not the same capacity as chabazite in exchanging NH4 with circulating solutions and plant root systems in soils. A comparison between samples from studied quarries is reported in Fig. 1. As can be observed the Sorano zeolitite shows the best features (e.g., high zeolite content and high CEC).

Arletti, R.; Maria, Giovanna Vezzalini; Quartieri, S. ( 2013 ) - “ImPACT” FIRB Futuro in Ricerca: Pressure-induced supermolecular organization of water and ethanol in all-silica zeolites. ( XVII National Congress of Catalysis GIC 2013 and XI National Congress of zeolites Science and Technology - - September, 15-18, 2013) ( - Congress abstracts ) (XVII National Congress of Catalysis GIC 2013 Bologna ITA ) - n. volume - - pp. da 34 a 34 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

In situ LS-XRPD experiments in high pressure using the pressure transmitting media methanol:ethanol:water 16:3:1 and ethanol:water 3:1. Penetration of water and ethanol molecules and formation of water and ethanol chains.

Arletti, R.; Quartieri, S.; Vezzalini, G.; Camara, F. ( 2013 ) - Dehydration dynamics of levyne: evidence of a new zeolite topology ( 17th International Zeolite Conference - - July, 7-12, 2013) ( - Atti del 17th International Zeolite Conference ) (- Moscow RUS ) - n. volume 1 - pp. da 109 a 110 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The high temperature behaviour of natural zeolite levyne was studied by in situ SR-XRPD. Water loss induces the cation migration toward the framework to obtain a better coordination, forcing the breaking of some T-O-T bridges and the consequent formation of new bonds and of a new structure. The 8mR bidimensional channel system of levyne is absent in the new topology and hence the molecular diffusion should be partially hindered in the dehydrated form.

Gigli, . L.; Agostini, G.; Arletti, R.; Fois, E.; Lamberti, C.; Tabacchi, G.; Quartieri, S.; Vezzalini, Maria Giovanna ( 2013 ) - Structural characterization of Fluorenone dye in Zeolite L ( 17th International Zeolite Conference - - July, 7-12, 2013) ( - Zeolites and ordered porous materials: bridging the gap between nanosciences and technology, Atti del 17th International Zeolite Conference ) (- Moscow RUS ) - n. volume 1 - pp. da 225 a 225 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The structural refinement of FL-ZL hybrid allowed to localize 1.7 FL molecules in the 12-ring channels. The strong interaction of FL carbonyl oxygen with K atoms is in line with the stability of this material under ambient conditions.

Gigli, L.; Arletti, R.; Quartieri, S.; Renzo, F. Di; Vezzalini, G. ( 2013 ) - The high thermal stabilility of the zeolite K-L: dehydration mechanism by in situ SR XRPD experiments ( 17th International Zeolite Conference - - July, 7-12, 2013) ( - Zeolites and ordered porous materials: bridging the gap between nanosciences and technology, Atti del 17th International Zeolite Conference ) (- Moscow RUS ) - n. volume 1 - pp. da 243 a 244 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Zeolite L has a very high thermal stability, maintains a good crystallinity up to 814 °C and can be classified as inflexible [4]. In particular, it is noteworthy that zeolite L undergoes a slight thermal expansion, which is very unusual for an alumino-silicate microporous material. Actually, while most of zeolites show the so-called negative thermal expansion [see 5 for a review], the positive one is observed in a number of neutral siliceous zeolites, like CIT-5, AlPO4-31and the one-dimensional 12MR system ITQ-4. In these materials the expansion is mainly realized along the direction of the main and large 12- or 14-ring channel [6], as observed in the zeolite L here investigated. Usually, in zeolites, most of the extraframework cations are coordinated by water molecules. Upon dehydration these cations move closer to the framework to form new bonds inducing strains on the framework, resulting in a structural deformation or even in bond breaking. Zeolite L represents an exception, because only one of the three cation sites (KD) is bonded to a water molecule, while the coordination spheres of the other cations are formed by only framework oxygen atoms. Moreover, among the five water sites, only two are at coordination distance from the framework oxygen atoms, while the others are involved only in water-water hydrogen bonds. These structural features explain why the dehydration process does not induce substantial structural modifications in the framework and why zeolite L even undergoes a small unit cell volume increase upon heating.

L.Leardini; S. Quartieri; G. Vezzalini; A. Martucci; V. Dmitriev ( 2013 ) - ELASTIC BEHAVIOR AND HIGH PRESSURE-INDUCED PHASE TRANSITION IN CHABAZITE: NEW DATA FROM A NATURAL SAMPLE FROM NOVA SCOTIA - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 170 - pp. da 52 a 61 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The high pressure behavior of a natural chabazite from Nova Scotia (Canada) [(Ca1.32K0.45Na0.13Sr0.10) [Si8.55Al3.45O24]center dot 11.30 H2O, s.g. R-3m, a = 9.38749(8) and alpha = 94.379(1)] was investigated by means of in situ synchrotron X-ray powder diffraction and silicone oil as non-penetrating P-transmitting medium, in the P-range from P-amb to 7.2 GPa. Above 2.1 GPa, a phase transition from rhombohedral to triclinic (pseudo-rhombohedral) symmetry is observed. The phase transition is accompanied by an abrupt decrease of most of the cell parameters and of the cell volume. Above the transition - between 2.5 and 5.9 GPa - the triclinic/pseudo-rhombohedral cell parameters decrease regularly, with a compressibility decrease relative to the trend observed before the transition. A further increase in compressibility occurs in the highest P regime, between 5.9 and 7.2 GPa. Overall, the cell volume decrease in the investigated P-range is 12.6%. Notwithstanding the abrupt and marked cell volume decrease accompanying the phase transition, this is reversible upon decompression. The refined elastic parameters were V-0 = 826(1) angstrom(3), K-0 = 54(3) GPa and V-0 = 784(2) angstrom(3), K-0 = 91(5) GPa, for the rhombohedral and triclinic phase, respectively. The results of the complete structural refinements performed up to 1.1 GPa indicated that: (i) the double-six-membered ring present in chabazite framework undergoes flattening as a result of a HP-induced cooperative tetrahedral anti-rotation; (ii) the 8-membered rings, limiting the channel apertures, become more circular and their crystallographic free area decreases; (iii) the extraframework content does not exhibit relevant modifications under pressure - as concerns the site occupancies - while some significant changes are observed in the bond distances. The elastic behavior and deformation mechanism of chabazite from Nova Scotia are compared with those of another chabazite sample from Vallerano and with those of other porous materials belonging to the 6-ring zeolite family.

L. Gigli; R. Arletti; S. Quartieri; F. Di Renzo; G. Vezzalini ( 2013 ) - The high thermal stability of the synthetic zeolite K-L: dehydration mechanism by in-situ SR-XRPD experiments - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 177 - pp. da 8 a 16 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Thermally induced structural modifications of a synthetic zeolite L [K8.46 (Al8.35 Si27.53) O7217.91H2O, framework type LTL, s.g. P6/mmm, a = 18.3367(1) and c = 7.5176(1) Å] were studied by temperatureresolved synchrotron X-ray powder diffraction. In the investigated temperature range (RT-814 C), neither structure breakdown nor phase transitions occurred. The largest unit cell deformation was observed between 100 and 240 C, accompanied by an increase and decrease of the a and c cell parameters, respectively. After complete water release, an inversion of the a and c parameter behavior was observed, while the cell volume continued to increase, although following a more flattened curve. Overall, in the investigated T range, a small cell volume increase of 0.7% was observed. The release of the five water molecules present in zeolite L started with the most weakly bonded one and occurred between 80 and 240 C. During dehydration the framework underwent minor rearrangements, which facilitated water release: the apertures of the main 12-ring and the 8-ring channels became more circular and the 6-membered rings became more hexagonal. The thermal expansion of zeolite L, very unusual for a non-siliceous zeolite, was interpreted and compared with previous data reported in literature for this porous material, and with the behavior of the synthetic phases ITQ-4 and CIT-5.

L. de Ferri; D. Bersani; Ph. Colomban; P. P. Lottici; G. Simon; G. Vezzalini ( 2012 ) - Raman study of model glass with medievalcompositions: artificial weathering andcomparison with ancient samples - JOURNAL OF RAMAN SPECTROSCOPY - n. volume - [Articolo in rivista (262) - Articolo su rivista]
Abstract

Potassium-rich ash-based glass is typical of medieval glass windows used in the Central Europe since 1000 A. D.. Glasses withmedieval-like composition were prepared with different amounts of K2O (15–20–25 K2O weight%) using recipes deduced fromarchaeometric literature. Raman data of these samples were interpreted on the basis of the Qn units model and of the polymerization index Ip and confirm a close dependence of glass depolymerization on the potassium content. Generally, K-basedglasses have high alteration sensitivity to pollutants conveyed by liquid or vapour water (rain, humidity and fog). In this work,the glass alteration processes were studied in terms of structural modifications related to the glass K content. Leaching andnetwork dissolution were investigated by attack with boiling concentrated sulfuric acid and by exposure to high temperatureand high pressure bidistilled water, respectively. The weight loss and alteration layer thickness were measured. The structuralchanges in the glass network and the presence of neoformation crystallized products were determined through linear Ramanmaps on altered glass cross sections. The more the glass network structure is depolymerized, the more the surface chemicalattack is facilitated. The results obtained for the model glasses are comparedwith those for a set of ancient K-rich glass fragments.

Cannavo', V.; Cardarelli, A.; Levi, S.T.; Lugli, S.; Vezzalini, G. ( 2012 ) - Archaeometrical investigation on Bronze age pottery from Po valley. ( VII Congresso Nazionale di Archeometria - - 22-24 febbraio 2012) ( - Atti del VII Congresso Nazionale di Archeometria ) (Patron Editore Bologna ITA ) - n. volume 1 - pp. da 4 a 4 ISBN: 978-88-555-3166-5 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The present work studies proto-historic pottery from Terramare Bronze Age settlements in the Po Plain, northern Italy. Ceramics from six Middle and Recent Bronze Age (XVII-XI cent. B.C.) sites in Modena Province (Montale, Gorzano, Castiglione di Marano, Cà de’ Monesi, Pontenuovo, Montebarello) were analysed to determine area of production, provenance of raw materials and specialization degree of manufacturing process. The physical-chemical characterization of the ceramics (177) and outcrop clays (38) was achieved by petrographic, mineralogical (XRD) and chemical analyses (XRF). The archaeometric investigation revealed a low carbonate matrix as a common feature of the whole pottery data-set, which can hence be assumed as the main marker to identify the possible raw materials. The standardization of the production process and the results of experimental reproductions suggest the existence of two different levels of complexity in pottery production (household and workshop), probably resulting from different systems of organization.

Arletti, R.; Lusetti, A.; Ferrari, D.; Vezzalini, G. ( 2012 ) - Archaeometrical analyses of early egyptian glass from Thebe area. ( VII Congresso Nazionale di Archeometria - - 22-24 febbraio 2012) ( - Atti del VII Congresso Nazionale di Archeometria ) (Patron Editore Bologna ITA ) - n. volume 1 - pp. da 161 a 161 ISBN: 978-88-555-3166-5 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

In this work a series of fragments of Egyptian unguentaria are characterized from the chemical and physical point of view. The analysed samples were produced in the first step of the Egyptian glass production, during the new Kingdom of Egypt. The glass production in Egypt started under Thumosis III kingdom and developed until it reached its maximum during the kingdom of Amenhotep III (XVIII dinasty, 1390-1352 BC.) e Amenhotep IV/Akhenaton (XVIII dinasty, 1352-1338 BC). In this period, different glass shapes and typologies appears, and also the variety of decorations and colours increased. The analysed samples pertain to six vessels (amphoriskoi and krateriskoi) coming from Thebes area and now stored at the Egyptian Museum of Turin (Italy) after the excavation carried out at the Valley of the Queens. All these vessels, are blue with yellow, white and turquoise decorations and were produced with the core forming technique. The chemical analyses of major and minor elements were performed by Electron Microprobe (EMPA). The nature of the opacifying and colouring agents was determined by X-ray powder diffraction. Since only micro volumes were sampled from the artefacts (less than 1 mm3), the diffraction experiments were successfully carried out using a single crystal diffractometer equipped with a CCD camera. The chemical data obtained show that all the samples contain high levels of Na2O. However, along with a number of glass containing rather high level of both MgO and K2O - thus classified as plant ash based glass - some of them show rather low levels of K2O along with high MgO percentages. Most of these low-potassium high-magnesium samples are Al- rich Co-bearing blue glass: this seems to indicate they were probably coloured with the addition of Co-bearing alum. This is also consistent with the high level of MnO present in these samples. This situation suggests the use of two different kinds of flux for the production of these glass: an organic source (for the production of most of yellow, white and turquoise glass) and an inorganic one (leading to lower levels of K and Mg) used for the production of the Co-bearing samples. Yellow opaque decorations are rich in Pb and Sb, while only Sb is present in the white and light blue ones. This is consistent with the results of the X-ray powder diffraction analyses, that confirmed the presence of lead antimonates in the yellow decorations and of calcium antimonates in white and light blue ones. No crystalline phases were detected in dark blue, black and violet bulk glass.

Ferri, L. De; Lorenzi, A.; Lottici, P.P.; Montenero, A.; Vezzalini, G. ( 2012 ) - Studio di trattamenti protettivi ibridi organico-inorganico per vetri da finestra antichi. ( VII Congresso Nazionale di Archeometria - - 22-24 febbraio 2012) ( - Atti del VII Congresso Nazionale di Archeometria ) (Patro Editore Bologna ITA ) - n. volume 1 - pp. da 169 a 169 ISBN: 978-88-555-3166-5 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Come noto, in antichità un’importante parte della produzione di vetro del centro Europa era finalizzata alla realizzazione di finestre per chiese/cattedrali e per l’edilizia civile. Il vetro prodotto durante il Medio Evo in quell’area è caratterizzato dalla presenza di potassio usato come agente fondente, che rende il vetro particolarmente sensibile ai fenomeni di alterazione dovuti all’azione degli agenti atmosferici. Poiché le strategie di conservazione sono indirizzate a mantenere i vetri da finestra nei loro originali contesti architettonici, è necessario proteggerli da ulteriori processi di degrado. Molti dei trattamenti applicati fino ad ora sono basati sull’uso di polimeri organici (resine epossidiche, polivinilacetati, acrilati). La tecnologia sol-gel a partire da alcossidi di silicio mostra importanti vantaggi nella preparazione di film in quanto la matrice è simile al vetro ma con proprietà aggiuntive come la resistenza chimica, la bassa viscosità e la buona adesione al substrato vetroso. I sol inoltre sono piuttosto stabili, possono essere facilmente applicate (a pennello o a spruzzo) senza danneggiare il substrato originale e con il minimo impatto visivo. Le problematiche legate alla reversibilità dei trattamenti vengono ormai sempre più accettate dagli esperti del settore del restauro. Poiché i vetri da finestra vengono attaccati da inquinanti atmosferici veicolati dalla presenza di acqua sotto forma liquida o vapore (pioggia, umidità atmosferica, nebbia) che agisce da agente di innesco per il processo di corrosione del vetro, sono stati studiati dei film idrorepellenti idrorepellenti in cui il TEOS (Tetra-etil-orto-silicato) è il precursore principale. I protettivi studiati contengono alcossidi di silicio funzionalizzati con diversi gruppi alchilici (di cui è stata variata la percentuale rispetto al TEOS), isopropanolo come solvente e contengono HCl come catalizzatore. I film protettivi sono stati applicati attraverso dip-coating a velocità controllata e trattati termicamente in stufa a 50°C per 1 ora. Sulla base delle misure di angolo di contatto statico e dinamico, svolte per testare le proprietà idrorepellenti delle superfici, e delle misure colorimetriche, finalizzate a verificare l’assenza di variazioni cromatiche, sono state selezionate le quattro migliori composizioni. I vetri potassici trattati sono stati poi sottoposti a processi di invecchiamento accelerato UV, testando due diverse sorgenti a diversa energia e potenza, e in atmosfera satura di SO2, variando la concentrazione del gas. Si è quindi dimostrato che i protettivi studiati sono compatibili con il substrato dal punto di vista chimico-fisico poiché sono a base di silice, non danno luogo a sottoprodotti di reazione, potenzialmente dannosi per il substrato antico, e sono trasparenti e incolori. I film ibridi hanno mostrato inoltre buone proprietà di idrorepellenza e sono risultati chimicamente stabili dopo le prove di invecchiamento accelerato.

Leardini, L.; Quartieri, S.; Vezzalini, G.; Martucci, A.; Dmitriev, V. ( 2012 ) - In-situ Synchrotron XRPD study of HP-induced phase transition in chabazite from Nova Scotia ( XX Convegno SILS - - July 18-20, 2012) ( - Atti del XX Convegno SILS ) (- Cosenza ITA ) - n. volume 1 - pp. da 74 a 74 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The high pressure behavior of a natural chabazite from Nova Scotia (Canada) [(Ca1.32K0.45Na0.13Sr0.10) [Si8.55Al3.45O24] 11.30 H2O, s.g. R-3m, a = 9.38749(8) and a = 94.379(1)] was investigated by means of in situ synchrotron X-ray powder diffraction and silicone oil as non-penetrating P-transmitting medium, in the P-range from Pamb to 7.2 GPa. Above 2.1 GPa, a phase transition from rhombohedral to triclinic (pseudo-rhombohedral) symmetry is observed. The phase transition is accompanied by an abrupt decrease of most of the cell parameters and of the cell volume. Above the transition – between 2.5 and 5.9 GPa – the triclinic/pseudo-rhombohedral cell parameters decrease regularly, with a compressibility decrease relative to the trend observed before the transition. A further increase in compressibility occurs in the highest P regime, between 5.9 and 7.2 GPa. Overall, the cell volume decrease in the investigated P-range is 12.6%. Notwithstanding the abrupt and marked cell volume decrease accompanying the phase transition, this is reversible upon decompression. The refined elastic parameters were V0 = 826(1) Å3, K0 = 54(3) GPa and V0 = 784(2) Å3, K0 = 91(5) GPa, for the rhombohedral and triclinic phase, respectively. The results of the complete structural refinements performed up to 1.1 GPa indicated that: (i) the double-six-membered ring present in chabazite framework undergoes flattening as a result of a HP-induced cooperative tetrahedral anti-rotation; (ii) the 8-membered rings, limiting the channel apertures, become more circular and their crystallographic free area decreases; (iii) the extraframework content does not exhibit relevant modifications under pressure – as concerns the site occupancies – while some significant changes are observed in the bond distances. The elastic behavior and deformation mechanism of chabazite from Nova Scotia are compared with those of another chabazite sample from Vallerano and with those of other porous materials belonging to the 6-ring zeolite family.

Gigli, L.; Agostini, G.; Arletti, R.; Fois, E.; Lamberti, C.; Tabacchi, G.; Quartieri, S.; Vezzalini, G. ( 2012 ) - Structural characterization of fluorenone in zeolite L by synchrotron X-ray powder diffraction. ( XX Convegno SILS - - July 18-20, 2012) ( - Atti del XX Convegno SILS ) (- Cosenza ITA ) - n. volume 1 - pp. da 53 a 53 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Zeolite L (ZL) framework  characterized by one-dimensional 12-ring channels is a versatile host material for the supramolecular organization of cromophore molecoles. The inclusion of dyes compounds into the channels is particularly intriguing, as the resulting host-guest compounds may exhibit unique properties, such as efficient energy transfer [1-3]. The lack of detailed structural informations about the orientation and alignment of the neutral dye fluorenone (FL) in the ZL pores suggested this study, aimed to understanding the functionality of these host-guest systems from the structural point of view. The ZL/FL hybrid complex was investigated by synchrotron X-ray powder diffraction experiments at GILDA beamline (ESRF, Grenoble). The loading of the dye on previously dehydrating the zeolite L was carried out by using gas-phase adsorption under vacuum, so to assure that water molecules did not block the pathway for molecule entering [4]. The diffraction data evidenced the embedding of FL into the channels, as well as the minor presence (7.4 %) of fluorenone molecules on the zeolite surface. As a consequence, the structure of FL-ZL hybrid was determined by a two-phases Rietveld refinement, in the hexagonal space group P6/mmm [5]. The relevant incorporation of FL into the channels of the dehydrated ZL was confirmed by a significant change of the unit cell parameters. 1.8 FL molecules per unit cell were located near the walls of the large 12-membered ring channel. A strong interaction between FL carbonyl group and the extraframework potassium cation is suggested by the short bond distances, and explains why FL is not displaced by water molecules when the FL-ZL hybrid is re-exposed to the air. Our experimental results are in good agreement with those obtained by molecular dynamics simulations on a less loaded hybrid [6].

Arletti, R; Quartieri, S; Vezzalini, G; Alvaro, M; Càmara, F ( 2012 ) - Dehydration dynamics of levyne: a combined synchrotron XRPD and single crystal diffraction study ( II European Mineralogical Conference - - 2-6/9/2012) ( - Atti of the II European Mineralogical Conference ) (EMC2012-PREVIEW Francoforte DEU ) - n. volume 1 - pp. da 1 a 1 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Zeolite dehydration has been widely studied because of the potential use of these porous phases as molecular sieves, sorbents, and catalysts. Knowledge of the structural modifications induced by temperature and of the stability field of these materials is of prime importance to assess their persistence and effectiveness in technological applications. The reversibility of dehydration process, which is considered one of the most remarkable properties of zeolites, is in general - but not always - completely fulfilled, at least in the short term. Some porous materials, when completely dehydrated, undergo irreversible changes in the framework topology. In general, these changes are due to the strain induced by migration of cations - initially located in the channels and surrounded by water molecules - to achieve a better coordination with framework anions after the water release. Notwithstanding the geological and technological interest for porous materials with levyne topology (LEV), its thermal behavior and stability has not been studied in detail up to now. In this work, the thermal induced structural modifications of a natural levyne (Ca7:8 Na2:2K1:1Al19:8Si31:2O108 51H2O, a= 13.3619(4) Å, c= 22.8820(1) Å, V = 3538.0(3) Å3, s.g. R?3m) were studied by both temperature-resolved synchrotron X-ray powder diffraction experiments (SR-XRPD), and by conventional-source high-temperature single crystal X-ray diffraction (SC-XRD). LEV framework consists of stacking 6-rings perpendicular to [0001] (6mRs?[0001]) in the sequence AABCCABBC.. . (Merlino et al. 1975). The repeat distance of this long sequence is about 22.90 Å. Between pairs of 6mRs?[0001] (d6R building units) are two levyne cages (LEV), which contain the non-framework cations and water molecules. One d6R and two LEV cages built up channels along [0001]. Moreover three equivalent channels, perpendicular to the threefold axis, confined by eight-membered rings are present in LEV-type framework. The SR-XRPD patterns were collected in continuum from room-T to 800°C, while single crystal experiments were performed at room-T, 30, 100 and 250°C. Below 100°C a lattice parameter increases, while c decreases, accounting for a very low volume decrease and only few water molecules are lost. Between 100 and 200 °C the release of more than 23 water molecules induces the cations migration toward the framework oxygen atoms, so to achieve a better coordination. Above 230°C, a further water loss induces the migration of Ca cations - previously hosted in the channels- inside the d6R building units, which are empty before the thermal treatment. This induces an abrupt cell volume reduction accompanied by symmetry reduction. No complete amorphization is observed up to the highest T studied. The X-ray structure refinement performed on the pattern collected upon reverse to room-T after transformation revealed that structural modifications are not reversible and the room-T cell parameters are not regained. Some aspects of levyne dehydration dynamics are similar to those found by Zema et al. (2008) for zeolite chabazite.

Arletti, R.; Quartieri, S.; Vezzalini, G.; Alvaro, M.; Càmara, F. ( 2012 ) - A new zeolite topology deriving from levyne dehydration. ( V International Workshop OXIDES 2012 joined with AIZ - - 23-27 September 2012) ( - Atti del V International Workshop OXIDES 2012 joined with AIZ ) (- Torino ITA ) - n. volume 1 - pp. da 158 a 158 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Knowledge of the structural modifications induced by temperature in zeolites and of their stability fields is of prime importance to assess zeolite persistence and effectiveness in their technological applications. Some porous materials, when completely dehydrated, undergo irreversible changes in the framework topology. In general, these changes are due to the strain induced by migration of cations - initially located in the channels and surrounded by water molecules - to achieve a better coordination with framework anions after the water release. Notwithstanding the spread interest for porous materials with levyne topology (LEV), their thermal behavior and stability have not been studied in detail up to now. In this work, the thermal induced structural modifications of a natural levyne from Fagridalur (Iceland) (Ca7.8 Na2.2K1.1Al19.8Si31.2O10851H2O, a= 13.3619(4) Å, c= 22.8820(1) Å, V = 3538.0(3) Å3, s.g. R-3m) were studied by both temperature-resolved synchrotron X-ray powder diffraction experiments (SR-XRPD), and by conventional-source high-temperature single crystal X-ray diffraction (SC-XRD). LEV framework consists of stacking 6-rings perpendicular to [0001] (6mR) in the sequence AABCCABBC (Merlino et al. 1975). Levyne cage is confined by two pairs of 6mR (D6R building units), and contains the non-framework cations and water molecules. A three-dimensional channel system, confined by 8-membered rings, lies perpendicular to [0001]. The SR-XRPD patterns were collected in continuum from room-T to 800°C, while SC-XRD experiments were performed at room-T, 30, 100 and 250°C. Below 100°C a lattice parameter increases, while c decreases, accounting for a very low volume reduction and few water molecule loss. Between 100 and 200 °C, the release of more than 23 water molecules induces the cations migration toward the framework oxygen atoms, so to achieve a better coordination. Above 230°C, a further water loss induces the breaking of the oxygen bridges in the D6R, the edge-sharing tetrahedral phenomenon and the rising of a new topology. The two phases coexist in a percentage about 50% up to the highest investigated temperature. The new framework consists of a sequence of a new zeolitic cage (Fig.1) and two cancrinite cages along [0001]. The structure – reported in the database of the hypothetical zeolite structure as 166_2_293 [2] –belongs to the ABC-6 family [3] and can be described with the following sequence: ABACACBCBA. The new cage can be described as a 20-hedron formed by fourteen 6mR and by six 4mR. The cations are distributed over 3 new sites: one at the center of the six membered ring shared by the two cancrinite cages, one near the center of the base of the new cage and one in a 6mR window of the new cage.

L. Leradini; S.Quartieri; Maria Giovanna Vezzalini; A. Martucci; V. Dmitriev ( 2012 ) - HP-induced phase transition in chabazite from Nova Scotia. ( Oxides 2012 joined with the Annual Meeting of the Italian Zeolites Association - - 23-27 September 2012) ( - Atti del convegno Oxides 2012 joined with the Annual Meeting of the Italian Zeolites Association ) (- Torino ITA ) - n. volume 1 - pp. da 176 a 176 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The high pressure behavior of a natural chabazite from Nova Scotia (Canada) [(Ca1.32K0.45Na0.13Sr0.10) [Si8.55Al3.45O24] 11.30 H2O, s.g. R-3m, a = 9.38749(8) and a = 94.379(1)] was investigated by means of in situ synchrotron X-ray powder diffraction and silicone oil as non-penetrating P-transmitting medium, in the P-range from Pamb to 7.2 GPa. Above 2.1 GPa, a phase transition from rhombohedral to triclinic (pseudo-rhombohedral) symmetry is observed. The phase transition is accompanied by an abrupt decrease of most of the cell parameters and of the cell volume. Above the transition – between 2.5 and 5.9 GPa – the triclinic/pseudo-rhombohedral cell parameters decrease regularly, with a compressibility decrease relative to the trend observed before the transition. A further increase in compressibility occurs in the highest P regime, between 5.9 and 7.2 GPa. Overall, the cell volume decrease in the investigated P-range is 12.6%. Notwithstanding the abrupt and marked cell volume decrease accompanying the phase transition, this is reversible upon decompression. The refined elastic parameters were V0 = 826(1) Å3, K0 = 54(3) GPa and V0 = 784(2) Å3, K0 = 91(5) GPa, for the rhombohedral and triclinic phase, respectively. The results of the complete structural refinements performed up to 1.1 GPa indicated that: (i) the double-six-membered ring present in chabazite framework undergoes flattening as a result of a HP-induced cooperative tetrahedral anti-rotation; (ii) the 8-membered rings, limiting the channel apertures, become more circular and their crystallographic free area decreases; (iii) the extraframework content does not exhibit relevant modifications under pressure – as concerns the site occupancies – while some significant changes are observed in the bond distances. The elastic behavior and deformation mechanism of chabazite from Nova Scotia are compared with those of another chabazite sample from Vallerano and with those of other porous materials belonging to the 6-ring zeolite family.

Leardini, L.; Quartieri, S.; Vezzalini, G.; Martucci, A.; Dmitriev, V. ( 2012 ) - Elastic behavior and high pressure-induced phase transition in chabazite: new data from a sample from Nova Scotia ( II European Mineralogical Conference - - 2-6/9/2012) ( - EMC2012-PREVIEW ) (- Francoforte DEU ) - n. volume 1 - pp. da 1 a 1 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Recently, the high pressure (HP) behavior of a natural chabazite from Vallerano [1] (VALL), and on the synthetic phases SAPO-34 [1] and ALPO-34 [2], was investigated in the frame of a wider project aimed at understanding the role of the framework/extraframework content on the compressibility of CHA-type porous materials. In this work, further structural information is obtained studying the response to HP of another natural chabazite sample from Nova Scotia (Canada) (NS) (s.g. R-3mR [3]), characterized by a different chemical composition with respect to VALL. The study was performed by means of in situ synchrotron X-ray powder diffraction (XRPD) and silicone oil as non-penetrating P-transmitting medium. XRPD experiments were performed in DAC at the BM01 beamline at ESRF (Grenoble, France) with a fixed =0.7355 Å. Powder patterns were collected from Pambup to 8.6 GPa and upon decompression. All the features of the Pamb pattern and the unit cell parameters are well recovered upon P release. Below 2.1 GPa, a and cell parameters slightly decrease and increase respectively with a resulting volume reduction of 3.6 %. Above 2.1 GPa, a transition to a triclinic P-1 pseudo-rhombohedral phase is observed. The rhombohedral to triclinic phase transition is accompanied by an abrupt decrease in the unit cell parameters and in the unit cell volume ( V=-4.0%). Between 2.5 and 5.9 GPa, the triclinic/pseudo-rhombohedral cell parameters decrease regularly and the unit cell volume variation ( V=-3.0%) indicates a lower compressibility with respect to that observed before the transition. In the highest P regime (5.9-7.2 GPa), a further slope change, with an increase in compressibility, is observed. As a whole, V between Pamb and 7.2 GPa is -12.6%. The elastic parameters, calculated with a second order BM-EoS, are V0 = 826 (1) Å3, K0 = 54(3) GPa and V0 = 784(2) Å3, K0 = 91(5) GPa, for the rhombohedral and triclinic phase, respectively. Preliminary results from Rietveld refinements up to about 1 GPa, suggest that the deformation mechanism acting in the low-P regime is a cooperative tilting of the tetrahedra belonging to the double 6-ring – resulting in a decrease of its thickness – accompanied by a simultaneous di-trigonalization of the two 6-rings. A similar mechanism was previously observed during compression of levyne [4]. The HP-induced cell volume contraction of NS (12.6 %) is higher than that of VALL (10.3%) in the same P range. This is congruent with the lower content in large extraframework potassium cations of NS, which contribute to sustain the porous structure in VALL.

Ferri, L. de; Lottici, P. P.; Vezzalini, G. ( 2012 ) - Raman study of artificially weathered medieval-type glass ( Xth Georaman meeting - - 11-13 June 2012) ( - Atti del Xth Georaman meeting ) (- Nancy FRA ) - n. volume 1 - pp. da 163 a 163 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Glass with Potash-Lime-Silica (PLS) composition were typically produced during the middle age in the central and northern Europe and are known to be very sensitive to the attack of the atmospheric pollutants. Since historical window glasses are in permanent contact with water in form of rain, fog, snow, or humidity, the alteration can easily take place initially through the leaching process. Consequently, the K+ extraction with the formation of a very strong dissociated base occurs in the liquid surface medium, leading to the dissolution of the glass network. Medieval-type PLS glass samples, containing different amounts of K2O (V1= ,V2=V3=) as fluxing agent, were produced and aged in concentrated boiling H2SO4 and in high temperature-high pressure water to simulate the two alteration processes (leaching and dissolution) separately. Aged samples were studied by Raman spectroscopy, performing linear sequences of spectra on their cross sections, and SEM-EDS technique, to identify the neo-formation crystalline phases and the alteration layer thickness. The leached samples (aged in sulphuric acid) displayed in the external part of the alteration layer the co-existence of Gypsum, Bassanite and Anhydrite. SEM images and EDS maps of S and Ca enhanced the presence of the Ca-sulphates as elongated crystals. The SEM observation of the glass samples subjected to the dissolution experiments generally showed the presence of abundant crystalline silicate phases, with different morphologies in the three chemically different samples. Moreover the EDS maps evidenced a slight impoverishment in Si and the accumulation of Ca in the surface layer. These samples displayed very complex Raman spectra where the contributions of different crystalline phases were found. V1 and V2 cross sections revealed, in addition to the glass signal, the features of the Ca- and K- phyllosilicates Gyrolite (Ca2Si3O7(OH)2) and Reyerite (KCa14Si24O60(OH)5•5H2O). In the V3 alteration layer the phases of the reyerite group were found together with hydroxyapatite (Ca5(PO4)3(OH)) and the hydrated Ca-K inosilicate charoite (K5Ca8(Si6O15)2Si2O9(OH).3(H2O)). The ICP-MS measurements, carried out on both ageing liquid media, indicated that the Ca content is very low (0.003-0.03 wt%) and this can be attributed to the crystallization of phases enriched in Ca that entrapped part of the Ca ions released by the glass.

Gigli, L.; Agostini, G.; Arletti, R.; Fois, F.; Lamberti, C.; Tabacchi, G.; Quartieri, S.; Vezzalini, G. ( 2012 ) - Dye molecules confined in nanopores: structural characterization of fluorenone in zeolite L ( Oxides 2012 joined with the Annual Meeting of the Italian Zeolites Association. - - Turin 23-27 September) ( - Atti del convegno Oxides 2012 joined with the Annual Meeting of the Italian Zeolites Association. ) (- Torino ITA ) - n. volume 1 - pp. da 169 a 169 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Zeolite L (ZL) framework - characterized by one-dimensional 12-ring channels - is a versatile host material for the supramolecular organization of cromophore molecules. The inclusion of dyes molecules into the channels is particularly intriguing, as the resulting host-guest compounds may exhibit unique properties, such as efficient energy transfer [1-3]. The lack of detailed structural information about the orientation and alignment of the neutral dye fluorenone (FL) in the ZL pores suggested this study, aimed to understanding the functionality of these host-guest systems from the structural point of view. The ZL/FL hybrid complex was investigated by synchrotron X-ray powder diffraction experiments (Fig. 1) at GILDA beamline (ESRF, Grenoble). The loading of the dye on previously dehydrating the zeolite L was carried out by using gas-phase adsorption under vacuum, so to assure that water molecules did not block the pathway for molecule entering [4]. The diffraction data evidenced the embedding of FL into the channels, as well as the minor presence (7.4 %) of fluorenone molecules on the zeolite surface. As a consequence, the structure of FL-ZL hybrid was determined by a two-phases Rietveld refinement, in the hexagonal space group P6/mmm [5]. The relevant incorporation of FL into the channels of the dehydrated ZL was confirmed by a significant change of the unit cell parameters. 1.8 FL molecules per unit cell were located near the walls of the large 12-membered ring channel (Fig. 2). A strong interaction between FL carbonyl group and the extraframework potassium cation is suggested by the short bond distances, and explains why FL is not displaced by water molecules when the FL-ZL hybrid is re-exposed to the air. Our experimental results are in good agreement with those obtained by molecular dynamics simulations on a less loaded hybrid [6] and will be compared with new computational data presently in progress.

Gigli, L.; Agostini, G.; Arletti, R.; Fois, E.; Lamberti, C.; Tabacchi, G.; Quartieri, S.; Vezzalini, G. ( 2012 ) - Confinement of dye molecules in nanopores: structural characterization of fluorenone in zeolite L by synchrotron X-ray powder diffraction ( II European Mineralogical Conference - - 2-6/9/2012) ( - EMC2012-PREVIEW ) (- Francoforte DEU ) - n. volume 1 - pp. da 1 a 1 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The understanding of the behavior of molecules inside porous materials under the combined effects of applied pressure, spatial confinement and constraints in morphology at the nanoscale is a challenge which has never been endeavored so far. One of the purposes of “ImPact” Project (financed by Italian MIUR, FIRB- Futuro in Ricerca 2013-2016) is to understand at atomistic level the supramolecular organization of different molecules in zeolites frameworks. In particular, the pressure-induced modifications of functional properties of hybrid materials (e.g. Zeolite L + organic colorants), currently applied in strategic areas, from sustainable energy technologies to biomedical sciences, are studied. Neutral dye fluorenone (FL) is able to form a stable host-guest complex with Zeolite L(ZL) - an appealing and excellent host for the supramolecular organization- and has received a considerable attention since it is a component of the energy relay system in artificial antennas [1,2]. Nevertheless, relatively few structural information, even at Pamb, is available about the orientation and alignment of the dye molecules in the zeolite pores. On the other hand, theoretical studies have shown that the orientation of fluorenone and the presence of water are parameters that strongly influence the light harvesting properties of this host-guest complex [3]. Hence, a detailed structural characterization is of great importance for understanding the functionality of these host-guest systems. In this study, three different FL/K-ZL materials have been synthesized by an increasing loading of FL in ratio of 0.5, 1.0, 1.5 and 2.0 molecules/unit cell. The samples obtained were characterized by means of X-ray powder diffraction, thermo-gravimetric analysis, IR and UV-vis spectroscopies at P amb. The incorporation of FL into the zeolite channels was confirmed by a significant change of the unit cell parameters and by drastic decrease in the ZL surface area also at low FL loading (Figure 1). The strong interaction between FL carbonyl group and the extraframework potassium cation, predicted by theoretical modelling [1], was confirmed by the short bond distances (2.77 Å), evidenced in the Rietveld refined structure, and by the shift of the C=O stretching frequency evidenced in the IR spectra. Such an interaction explains why FL is not displaced by water molecules when FL/ZL hybrid is re-exposed to the air [1]. Interestingly, although the UV-vis absorption spectrum was almost unaffected by the FL loading, the corresponding emission spectrum evidenced a strong influence: the optimum FL/K-LTL ratio was then determined in order to optimize the performances of the device as light harvester. The structural information obtained theoretically and from XRD allowed also to explain the loading dependence of the optical properties of the material and to correlate it with the relative orientation of the fluorenone molecules in the zeolite channels.

V. Cannavò; A: Cardarelli; S.T. Levi; S. Lugli; G. Vezzalini ( 2012 ) - Pottery production in bronze age settlements of the Modena area (Northern Italy) ( AIAR VII Congresso Nazionale di Archeometria - - 22-24 febbraio 2012) ( - Atti del Congresso A.I.Ar. 2012 Modena ) (Patron Bologna ITA ) - pp. da 1 a 32 ISBN: 9788855531665 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

The present work studies proto-historic pottery from Terramare Bronze Age settlements in the Po Plain, northern Italy. Ceramics from six Middle and Recent Bronze Age (XVII-XI cent. B.C.) sites in Modena Province (Montale, Gorzano, Castiglione di Marano, Cà de’ Monesi, Pontenuovo, Montebarello) were analysed to determine area of production, provenance of raw materials and specialization degree of manufacturing process. The physical-chemical characterization of the ceramics (177) and outcrop clays (38) was achieved by petrographic, mineralogical (XRD) and chemical analyses (XRF). The archaeometric investigation revealed a low carbonate matrix as a common feature of the whole pottery data-set, which can hence be assumed as the main marker to identify the possible raw materials. The standardization of the production process and the results of experimental reproductions suggest the existence of two different levels of complexity in pottery production (household and workshop), probably resulting from different systems of organization.

L. DE FERRI; D. BERSANI; A. LORENZI; P.P. LOTTICI; A. MONTENERO;S. QUARTIERI; G. VEZZALINI ( 2012 ) - CONSERVAZIONE E RESTAURO DI VETRATE ANTICHE: DATI PRELIMINARI SULLA RIPRODUZIONE DI VETRI MEDIOEVALI ( - Atti del VI Congresso Nazionale AIAr- SCIENZA E BENI CULTURALI ) (Patron Editore Bologna ITA ) [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Allo scopo di realizzare trattamenti protettivi per vetrate medioevali, sono stati prodotti campioni di vetro la cui composizione chimica riproduc-+e quella tipica dei vetri da finestra prodotti nel Nord Europa a partire dal 1000 d.C. I campioni sono stati realizzati con quantità diverse di fondente potassico (K2O: 15-20-25 % in peso); le composizioni e le condizioni di sintesi sono state ottimizzate sulla base dei risultati di studi archeometrici riportati in letteratura e il metodo di preparazione è stato sviluppato variando le materie prime, il tipo di crogiolo, le rampe termiche, e le modalità di raffreddamento. I campioni sono stati sottoposti ad annealing per eliminare le tensioni residue dovute al raffreddamento. I vetri sono stati caratterizzati tramite analisi chimica XRF, XRPD e tecniche spettroscopiche Raman e XANES. In particolare la spettroscopia Raman si è dimostrata una tecnica rapida e non distruttiva per la determinazione della composizione chimica e della struttura dei vetri antichi. Inoltre si è verificato che il ferro si trova principalmente nello stato di ossidazione 3+ e in geometria tetraedrica, agendo così da formatore di reticolo.

R. Arletti; D. Ferrari; G. Vezzalini ( 2012 ) - Pre-Roman glass from Mozia (Sicily-Italy): the first archaeometrical data - JOURNAL OF ARCHAEOLOGICAL SCIENCE - n. volume 39 - pp. da 3396 a 3401 ISSN: 0305-4403 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This study present the results of an archaeometrical investigation performed on a series of opaque pre-Roman glass (vessels and ornaments) dated from the 6th to 4th century BC coming from Sicily. Sixteen core formed vessels, twelve beads, three pendants and one spindle-whorl recovered in the Phoenician-Punic sites of Mozia and Birgi were analysed thought a micro destructive approach. The complete chemical analyses and X-Ray diffraction analyses were performed on small fragments of glass. The aims of this work are: 1) to obtain a chemical characterization of these samples in order to understand the raw materials employed for their production; 2) to obtain information regarding the opacifying phases dispersed in the glass; 3) to make a comparison with the results recently obtained on coeval and similar finds recovered in other cultural context, in particular in Northern Italian Etruscan contexts in order to understand whether they could belong to the same Greek-Eastern production. The chemical data of these samples confirm they are silica soda lime glass produced with natron. The opaque decorations of the samples were done by using Sb based opacifiers. The major and minor analyses of the majority of the samples seem to suggest a common origin with the coeval material found in Northern Italian context. On the contrary, for some artifacts, in particular the pendants, a Phoenician-Punic origin is supposed.

L. Leardini; S. Quartieri; A. Martucci; G. Vezzalini; V. Dmitriev ( 2012 ) - COMPRESSIBILITY OF MICROPOROUS MATERIALS WITH CHA TOPOLOGY: 2. ALPO-34. - ZEITSCHRIFT FUR KRISTALLOGRAPHIE - n. volume 227 - pp. da 514 a 521 ISSN: 0044-2968 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The HP behavior of ALPO-34 as-synthesized was investigated by means of in-situ synchrotron X-ray powder diffraction, in the frame of a wider project aimed at understanding the role of the framework/extraframework content in the P-induced deformation mechanisms of natural and synthetic microporous materials with CHA framework topology. ALPO-34 compressibility under non-penetrating P transmitting medium was determined up to 6.0 GPa and upon decompression to Pamb. After an initial large structure deformation at P < 0.4 GPa, a regular volume reduction was observed up to about 3 GPa. Above 3.1 GPa, an abrupt change in the behavior of all cell parameters was observed, accompanied by an evident decrease in compressibility. The isothermal Equation of State (EoS), refined with a II-order Birch–Murnaghan EoS from 0.4 to 3.1 GPa, yielded the following parameters: V0 ¼ 755(1)A˚ 3, K0 ¼ 54(3) GPa. No complete X-ray amorphization was achieved up to the highest investigated P value. A complete reversibility of the unit cell parameters was observed upon P release. The compressibility behavior of ALPO-34 was compared with that of the other CHA-type zeolites. The volume reduction observed for natural chabazite, and for SAPO-34 and ALPO-34 assynthesized, was 6.2%, 9.4%, and 6.0%, respectively. Notwithstanding the presence of morpholine molecules, as a structure directing agent, in the two as-synthesized phases, they exhibited significantly different compressibility. This can be interpreted as due to the octahedral coordination of part of the ALPO-34 framework aluminum, leading to a more rigid framework compared to that of SAPO-34, which contains only tetrahedral aluminum.

L. DE FERRI; D. BERSANI; A. LORENZI; P. P. LOTTICI; A. MONTENERO; G. VEZZALINI; G. SIMON ( 2012 ) - Structural and vibrational characterization of medieval like glass samples - JOURNAL OF NON-CRYSTALLINE SOLIDS - n. volume 358 - pp. da 814 a 819 ISSN: 0022-3093 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Within the framework of a project aimed to develop protective coatings for antique glass windows, three glass varieties of medieval-like composition were prepared using recipes deduced from archaeometric studies and different amounts of potassium for fluxing (15–20–25 K2O wt.%). Batches were melted in mullite crucibles using an electric furnace at 1350 °C, the glass was fast cooled in air and annealed at temperatures 20 °C higherthan the sample glass transition temperatures (726, 702 and 683 °C for V1, V2 and V3, respectively). The chemical composition of the glasswas determined by X-Ray Fluorescence Spectroscopy (XRF) and the glass transition temperature was checked by differential thermal analysis (DTA). X-Ray Powder Diffraction (XRPD) data and vibrational spectroscopic experiments (FT-IR and Raman) revealed a direct dependence of glass de-polymerization on potassiumcontent. In particular, the Raman datawere interpreted on the basis of SiO4 structural units Qn andthe polymerization index Ip.

S. Quartieri; R. Arletti; G. Vezzalini; F.Di Renzo; V. Dmitriev ( 2012 ) - ELASTIC BEHAVIOR OF MFI-TYPE ZEOLITES: 3- COMPRESSIBILITY OF SILICALITE AND MUTINAITE - JOURNAL OF SOLID STATE CHEMISTRY - n. volume 191 - pp. da 201 a 212 ISSN: 0022-4596 [Articolo in rivista (262) - Articolo su rivista]
Abstract

We report the results of an in-situ synchrotron X-ray powderdiffra ction study–performedusing silicone oil as‘‘non-penetrating’’ pressure transmitting medium– of the elastic behavior of three zeolites with MFI-type framework: the natural zeolite mutinaite and two silicalites (labeledAandB) synthesized under different conditions. While in mutinaite no symmetry change is observed as a function of pressure, a phase transition from monoclinic (P21/n) to orthorhombic (Pnma) symmetry occurs at about 1.0GPa in the silicalite samples. This phase transition is irreversible upon decompression. The second order bulk moduli of silicalite A and silicalite B, calculated after the fulfillment of thephase transition, are: K0=18.2(2)and K0=14.3 (2)GPa, respectively. These values make silicalite the most compressible zeolite among those up to now studied in silicone oil. The structural deformations induced by HP in silicalite A were investigated by means of complete Rietveld structural refinements, before and after the phase transition,at Pamb and 0.9GPa,respectively.The elastic behaviors of thethree MFI- type zeolites here investigated were compared with those of Na-ZSM-5 and H-ZSM-5, studied in similar experimental conditions: the two silicalites–which are the phases with the highestSi/Al ratios and hence the lowest extraframework contents–show the highest compressibility. On the contrary, the most rigid material is mutinaite, which has a very complex extraframework composition characterized by a high number of cations and wate rmolecules.

De Ferri, L.; Bersani, D.; Colomban, Ph.; Lottici, P.P.; Simon, G.; Vezzalini, Maria Giovanna ( 2011 ) - Aging of medieval-like model glass. ( Technart 2011 - - 2011 April 26-29) ( - Abstracts of the conference Technart 2011 ) (Technart Berlin DEU ) - n. volume - - pp. da 112 a 112 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The most characteristic feature of northern European medieval glass, used in the cathedral windows, is the high content of K2O and CaO, resulting from the use, after 1000 A.D, of beech and fern ashes as fluxing agents. Three glass varieties with medieval-like composition were prepared using recipes deduced from archaeometric studies with different amounts of potassium for fluxing (15 - 20 - 25 K2O weight %). Aging experiments were carried out on the reproduced glass samples by exposure to boiling concentrated sulfuric acid and to high temperature and high pressure bi-distilled water. The glass weight loss and the alteration layer thickness were measured and the aging solutions were analyzed through AAS to detect K+ ions release. For the water attack experiments the pH of the solution was checked over time. Changes in the glass network structure and the presence of neo-formation products were determined by Raman maps recorded on altered glass cross sections and X-ray powder diffraction.

De Ferri L.; Bersani D.; Colomban Ph.; Lottici P.P.; Simon G.; Vezzalini Maria Giovanna ( 2011 ) - Aging of PLS-glass: Study of the alteration phenomena. ( GLASSAC11, Glass science in art and conservation - - 10-12 May 2011) ( - GLASSAC11, Glass science in art and conservation ) (FRAUNHOFER VERLAG - DEU ) - n. volume 1 - pp. da 103 a 105 ISBN: 978-3-8396-0255-3 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The wood ash-based glass (PLS, potash-lime-silica), employed for medieval cathedral windows in Northern Europe since 1000 A.D., is particularly sensitive to the alteration phenomena. Three PLS medieval-like glass were produced with different K2O content and characterized by FT-IR and Raman spectroscopy. Aging experiments were carried out by sulfuric acid and water, checking, in this last case, the pH over time. The weight loss and the alteration layer thickness were measured and the interacting solutions were analyzed through AAS. Raman maps were recorded on the altered glass cross sections. Changes in the glass network structure were observed and the presence of neo-formation products was determined.

Arletti, R.; Quartieri, ; S, .; Vezzalini, G. ( 2011 ) - High-pressure behavior of high silica ferrierite ( XXII Congress of International Union of Crystallography - - 22-30 August 2011) ( - Atti del XXII Congress of International Union of Crystallography ) (International Union of Crystallography. Published by John Wiley & Sons Ltd Hoboken, NJ USA ) - ACTA CRYSTALLOGRAPHICA. SECTION A, FOUNDATIONS OF CRYSTALLOGRAPHY - n. volume A67 - pp. da 243 a 244 ISSN: 0108-7673 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

Ferrierite (FER framework topology) is a well-known aluminosilicate zeolite mineral. An understanding of the structure and properties of FER remains important because of its role as a catalyst in commercial reactions. For example, it is important in the petrochemical industry, where it has been used as a shape selective catalyst for the production of isobutene. The thermal behavior of this phase (in its high silica form) was recently studied by Bull et al [1], while its compressibilty has never been investigated before. The high pressure (HP) behavior of synthetic high silica zeolite ferrierite (FER) was investigated by means of in-situ synchrotron X-ray powder diffraction, with the aim to understand the P-induced deformation mechanism. The microporous material was sinthesized starting from pure silica and pyridine and propyl-amine as structure directing agents. Here we report the preliminary results on the compressibility of the as synthesized phase. The study of the compressibility of the calcined one will be carried out in the following steps of the project.The crystal structure of ferrierite is built up of rings of fivecornershared SiO4 tetrahedra (known as five-membered ringsor 5MRs) building units, which form layers in the ab plane.The layers are connected to form a matrix of 10MR channels running parallel to the c axis, which are intersected by 8MR channels running parallel to the b axis. Six-membered rings connect the 10MRs alongthe c axis direction. The HP diffraction experiments were performed at BM01a beamline (ESRF), at the fixed wavelength of 0.71 Å, using a modified Merril- Basset DAC and a mixture of methanol- ethanol and water (16:3:1) as penetrating P-transmitting medium. The powder patterns were collected from Pamb to 6.2 GPa. Some patterns were also measured upon pressure release up to Pamb, to check the reversibility of the compression effects. The unit cell parameters were refined by means of Rietveld method. The main results of this study are: 1) No complete X-ray amorphization is observed up to about 6.6 GPa; 2) No abrupt change of the elastic behavior is observed in the whole pressure range. Between Pamb and 6.2 GPa the reduction of the cell parameter are 4%, 5% and 6% for a, b and c respectively, accounting for a volume reduction of about 14 %. 3) The bulk modulus obtained using a second order Birch-Murnaghan equation of state and data weighted by the uncertainties in P and V was K0 = 30.1(3) GPa. This compressibility determined in m.e.w. is one of the highest when compared with other natural and synthetic zeolites studied with “penetrating” aqueous media [2], [3]. 4) The P-induced effects on as-syntehsized ferrierite structure are completely reversible.

De Ferri, L.; Bersani, D.; Colomban, Ph.; Lottici, P.P.; Simon, G.; Vezzalini, Maria Giovanna ( 2011 ) - Raman study on medioeval-like glass samples: glass characterization, artificial weathering and comparison with ancient K-based glasses ( 6th International Congress on the Application of Raman Spectroscopy in Art and Archaelogy - - 5-8 September 2011) ( - Atti del 6th International Congress on the Application of Raman Spectroscopy in Art and Archaelogy ) (- Parma ITA ) - n. volume 1 - pp. da 28 a 28 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Potassium-rich ash-based glass is typical of medieval glass windows used in the Central Europe since 1000 A. D.. Glasses with medieval-like composition were prepared with different amounts of K2O (15–20–25 K2O weight%) using recipes deduced from archaeometric literature. Raman data of these samples were interpreted on the basis of the Qn units model and of the polymerization index Ip and confirm a close dependence of glass depolymerization on the potassium content. Generally, K-based glasses have high alteration sensitivity to pollutants conveyed by liquid or vapour water (rain, humidity and fog). In this work, the glass alteration processes were studied in terms of structural modifications related to the glass K content. Leaching and network dissolution were investigated by attack with boiling concentrated sulfuric acid and by exposure to high temperature and high pressure bidistilled water, respectively. The weight loss and alteration layer thickness were measured. The structural changes in the glass network and the presence of neoformation crystallized products were determined through linear Raman maps on altered glass cross sections. The more the glass network structure is depolymerized, the more the surface chemical attack is facilitated. The results obtained for the model glasses are comparedwith those for a set of ancient K-rich glass fragments.

Arletti, R.; Quartieri, S; Vezzalini Maria Giovanna ( 2011 ) - Compressibility behaviour of as-synthesized high-silica Ferrierite. ( XL Congresso Associazione Italiana Cristallografia (AIC), - - 19-22 September 2011) ( - Atti del XL Congresso Associazione Italiana Cristallografia (AIC), ) (- Siena ITA ) - n. volume 1 - pp. da 31 a 31 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Ferrierite (FER framework topology) is a well-known aluminosilicate zeolite mineral. An understanding of the structure and properties of FER remains important because of its role as a catalyst in commercial reactions. For example, it is important in the petrochemical industry, where it has been used as a shape selective catalyst for the production of isobutene. The thermal behavior of this phase (in its high silica form) was recently studied by Bull et al [1], while its compressibilty has never been investigated before. The high pressure (HP) behavior of synthetic high silica zeolite ferrierite (FER) was investigated by means of in-situ synchrotron X-ray powder diffraction, with the aim to understand the P-induced deformation mechanism. The microporous material was synthesized starting from pure silica and pyridine and propyl-amine as structure directing agents. Here we report the preliminary results on the compressibility of the as-synthesized phase. The study of the compressibility of the calcinated one will be carried out in the following steps of the project. The crystal structure of ferrierite is built up of rings of fivecorner-shared SiO4 tetrahedra (known as five-membered ringsor 5MRs) building units, which form layers in the ab plane. The layers are connected to form a matrix of 10MR channels running parallel to the c axis, which are intersected by 8MR channels running parallel to the b axis. Six-membered rings connect the 10MRs alongthe c axis direction. The HP diffraction experiments were performed at BM01a beamline (ESRF), at the fixed wavelength of 0.71 Å, using a modified Merril-Basset DAC and a mixture of methanol:ethanol:water (16:3:1) as P-transmitting medium. The powder patterns were collected from Pamb to 6.2 GPa. Some patterns were also measured upon pressure release up to Pamb, to check the reversibility of the compression effects. The unit cell parameters were refined by means of Rietveld method. The main results of this study are: 1) No complete X-ray amorphization is observed up to about 6.6 GPa; 2) No abrupt change of the elastic behavior is observed in the whole pressure range. Between Pamb and 6.2 GPa the reduction of the cell parameter are 4%, 5% and 6% for a, b and c respectively, accounting for a volume reduction of about 14 %. 3) The P-induced effects on the as-synthesized Si-ferrierite cell parameters are completely reversible. 4) The bulk modulus obtained using a second order Birch-Murnaghan equation of state and data weighted by the uncertainties in P and V was K0 = 30.1(3) GPa. This compressibility is one of the highest when compared with the other natural and synthetic zeolites studied with “penetrating” aqueous media [2, 3] and is very similar to that of SAPO-34 [4], another microporous material studied at HP in its as-synthesized form containing the organic template.

Montagna G.; Arletti R.; Vezzalini G.; Di Renzo F. ( 2011 ) - Borosilicate and aluminosilicate pollucite nanocrystals for the storage of radionuclides - POWDER TECHNOLOGY - n. volume doi:10.1016/j.powtec.2010.08.048 - pp. da 491 a 495 ISSN: 0032-5910 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Cesium can be encapsulated in crystalline aluminosilicates or borosilicates of ANA framework type byhydrothermal synthesis from alkaline solutions at a temperature as low as 115 °C. No miscibility gap isobserved in the borosilicate–aluminosilicate solid solution. The presence of cesium in the synthesis batchslightly decreases the yield of incorporation of boron in the silicate framework. Nanocrystals from 25 to50 nm are formed in most of the synthesis conditions.

Arletti R.;Rivi L.; Ferrari D.;Vezzalini G. ( 2011 ) - THE MEDITERRANEAN GROUP II: ANALYSES OF VESSELS FROM ETRUSCAN CONTEXTS IN NORTHERN ITALY - JOURNAL OF ARCHAEOLOGICAL SCIENCE - n. volume 38 - pp. da 2094 a 2100 ISSN: 0305-4403 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A large sample set of transparent and opaque glass artefacts recovered from Etruscan contexts innorthern Italy (Bologna and Spina (FE) necropoleis) and dated to a period between the 6th and 4thcentury BC are analysed in this paper. Samples of highly decorated beads, spindle whorls and vessels ofthe ‘Mediterranean Group I’ (Alabastron, Oinochoes, Amphoriskos) were selected in order to determinewhether these different glass artefacts were produced at the same manufacturing site. While the vesselsalmost certainly originate from Greece, the beads could derive from a more ancient local productionascertained at the site of Frattesina (Rovigo, Italy) and dated to the Bronze Age.The aims of this study are: (i) to characterise a set of Iron Age glass artefacts, thus providing newquantitative chemical data; and (ii) to identify possible differences between finds recovered fromdifferent localities and between glass vessels and beads, in order to establish whether different manufactureswere active contemporaneously.The chemical analyses of major and minor elements were performed with an electron microprobe. Thenature of the opacifying and colouring agents was determined by X-ray diffraction. The sample set isrelatively homogeneous and most of the samples can be classified as low magnesium glass. The yellowopaque decorations are rich in Pb and Sb, while only Sb is present in the white and light blue samples.The XRD analyses confirmed the presence of lead antimonates in the yellow decorations and of calciumantimonates in the white and light blue decorations.

ROSSELLA ARLETTI; Maria GIOVANNA VEZZALINI;CESARE FIORI; MARIANGELA VANDINI ( 2011 ) - MOSAIC GLASS FROM ST PETER’S, ROME:MANUFACTURING TECHNIQUES AND RAW MATERIALSEMPLOYED IN LATE 16TH-CENTURY ITALIANOPAQUE GLASS - ARCHAEOMETRY - n. volume 53 - pp. da 364 a 386 ISSN: 0003-813X [Articolo in rivista (262) - Articolo su rivista]
Abstract

A recent restoration of late 16th-century mosaics in one of the vaults beneath the dome of St Peter’s Basilica in Rome allowed sampling and analysis of a group of glass tesserae. The aimof this work is the characterization of opaque coloured glasses possibly produced in Rome.The characteristics of the glass from St Peter’s were compared with those of Venetian and Tuscan production, in order to assess possible common origins. Chemical analysis of 30 samples was carried out by electron microprobe, while the nature and morphology of opacifiers were determined by X-ray diffraction and scanning electron microscopy. Almost all the opaque samples were characterized by the presence of SnO2 crystals. In addition, depending on the colour of the glass, other crystalline phases were identified: lead-tin oxide (PbSnO3) in yellow glass, cuprite (Cu2O) in orange glass and two calcium-tin silicates with differentstoichiometry (CaSnSiO5 and Ca3SnSi2O9) in the green-yellow variety. A frame of reference for identifying raw materials and glass-making techniques is provided by textual sources, hereexamined in comparison with the compositional characteristics of the tesserae from St Peter’s.

Arletti R.; Vezzalini G.; Morsli A.; Di Renzo F.; Dmitriev V.;Quartieri S. ( 2011 ) - Elastic behavior of MFI-type zeolites: 1-Compressibility of Na-ZSM-5in penetrating and non-penetrating media - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 142 - pp. da 696 a 707 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Na-ZSM-5, performed using both silicone oil (s.o.) and (16:3:1) methanol:ethanol:water (m.e.w.), as ‘‘non-penetrating’’ and ‘‘penetrating’’ pressure transmitting media, respectively. In the range from ambient pressure (Pamb) to 6.2 GPa, the reductions of a, b, c, and V observed in s.o. are: 6.4, 6.3, 6.9 and 18.5%,respectively. From Pamb to 7.4 GPa, a unit-cell volume reduction of about 14.6% is observed for Na-ZSM-5 compressed in m.e.w., and the corresponding reductions of a, b, and c cell parameters are 6.3, 4.6, and 4.5%, respectively. In both cases no phase transitions are observed and the unit cell parameters of ambientconditions are recovered upon decompression. The complete structural refinements relative to the experiments performed in m.e.w. up to 1.6 GPa reveal a strong increase in the extra-framework content – with the penetration of additional water/alcohols molecules in the partially occupied extra-framework sites of as-synthesized Na-ZSM-5. This P-induced penetration, which does not induce any cell volumeexpansion, is only partially reversible, since a fraction of the extra-molecules remains in the channels upon decompression. Our results show that Na-ZSM-5 is the softest microporous material among those so far compressed in s.o. Moreover, its compressibility is higher in s.o. than in m.e.w. (K0 = 18.2(6) GPa,K0 = 4 (fixed) and 28.9(5) GPa, K0 = 4 (fixed), respectively). This can be ascribed to the penetration of the extra-water/alcohol molecules, which contribute to stiffen the structure and to contrast the channel deformations.

S. Quartieri; G. Montagna; R. Arletti; G. Vezzalini ( 2011 ) - Elastic behavior of MFI-type zeolites: Compressibility of H-ZSM-5 in penetrating and non-penetrating media. - JOURNAL OF SOLID STATE CHEMISTRY - n. volume 184 - pp. da 1505 a 1516 ISSN: 0022-4596 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The elastic behavior of H-ZSM-5was investigated by in-situ synchrotron X-ray powder diffraction, using both silicone oil (s.o.) and (16:3:1) methanol:ethanol:water (m.e.w.) as ‘‘non-penetrating’’ and ‘‘penetrating’’ pressure transmitting media, respectively. From Pamb to 6.2GP the volumereductionobserved in s.o. is 16.6%. This testifies that H-ZSM-5 is one of the most flexible microporous materials up to now compressed in s.o. Volume reduction observed in m.e.w. up to 7.6GPa is 14.6%. Astrong increase in the total electron number of the extraframeworks ystem, due to the penetration of water/alcohol molecules in the pores, is observed in m.e.w. This effect is the largest up to now observed inzeolites undergoing this phenomenon without cell volume expansion. The higher compressibility ins.o.than in m.e.w.can be ascribed to the penetration of the extra-water/alcohol molecules, which stiffenthe structure and contrast the channel deformations.

R. Arletti; E. Bertoni; G. Vezzalini; D. Mengoli ( 2011 ) - Glass beads from Villanovian excavations in Bologna (Italy): an archaeometrical investigation - EUROPEAN JOURNAL OF MINERALOGY - n. volume 23 - pp. da 959 a 968 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Excavations performed in the 1970s in the present-day trade fair zone of Bologna brought to light remains of civilisationsof the 8–7th century B.C. Archaeological studies identified a large number of objects which clearly indicated the existence of anextensive Villanovian village. Fifteen blue, turquoise, and dark green glass beads were selected and analysed in the present study.Chemical analyses of major and minor elements were obtained by EMPA, whereas trace elements were determined on selectedsamples by LA-ICP-MS. The occurrence of eventual opacifying agents dispersed in the matrix was attested by SEM observations.The chemical data allow identification of a group of four beads characterised by a mixed alkali composition, typical of FrattesinaFinal Bronze Age production. All the other samples have low levels of K2O (,2 wt%) and relatively high Na2O (.15 wt%). Among these last samples, which can be classified as natron-based glass, a number of blue beads show a high quantity of MgO (about 3 wt%), in combination with a low K2O amount. These low-K, high-Mg glasses also exhibit extremely high amounts of Al2O3, possibly due to the use of Co-bearing alum as colouring compound. Also the trace-element data confirm the division of the natron-based samples into two different sub-groups on the basis of the concentration of V, Cr, Ti and Zr. This suggests that the glass found at this site derivesfrom three different melts. Regarding the opacity of the samples, in most of the cases this effect is due to the dark colour of the glass (i.e., blue, dark green) which hinders the transmission of light. Crystalline particles of calcium antimonate were found only in the turquoise-colour samples.

Leardini, L.; Quartieri, S.; Vezzalini, Maria Giovanna ( 2010 ) - Compressibility of microporous materials with CHA topology: 1. Natural chabazite and SAPO-34 - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 127 - pp. da 219 a 227 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The HP behaviors of a natural chabazite and of SAPO-34 as synthesized wereinvestigated by means of in-situ synchrotron X-ray powder diffraction, with the aim of understandingthe role of the framework/extraframework content on the response to pressure. Compressibility wasdetermined with silicon oil, as non-penetrating P-transmitting medium, up to 7.6 GPa and 4.5 GPafor chabazite and SAPO-34, respectively. The isothermal Equation of States (EoS), refined with athird-order (chabazite) and a second order (SAPO-34) Birch-Murnagan EoS, yielded the followingparameters: V0=839(1) Å3, K0 = 41(3) GPa, Kp = 11(2) GPa, and V0=2439(4) Å3, K0 = 29(1)GPa, for chabazite and SAPO-34, respectively. These results indicate that chabazite is lesscompressible than SAPO-34. This is mainly ascribed to the more complex and hindering extraframeworkcontent of the natural sample. No complete structural refinements of the powderpatterns were performed, but the compressibility of these materials with CHA topology wastentatively interpreted on the basis of the deformation mechanism observed in the structurallyrelated zeolite levyne. The comparison between the volume decrease induced on chabazite by highpressure and by high temperature indicates that this zeolite is much more flexible undercompression than upon dehydration.

Arletti, R.; Maiorano, C.; Ferrari, D.; Vezzalini, Maria Giovanna; Quartieri, S. ( 2010 ) - The first archaeometric data on polychrome Iron Age glass from sites located in northern Italy - JOURNAL OF ARCHAEOLOGICAL SCIENCE - n. volume 37 - pp. da 703 a 712 ISSN: 0305-4403 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A large sample set of transparent and opaque glass artefacts recovered from Etruscan contexts innorthern Italy (Bologna and Spina (FE) necropoleis) and dated to a period between the 6th and 4thcentury BC are analysed in this paper. Samples of highly decorated beads, spindle whorls and vessels ofthe ‘Mediterranean Group I’ (Alabastron, Oinochoes, Amphoriskos) were selected in order to determinewhether these different glass artefacts were produced at the same manufacturing site. While the vesselsalmost certainly originate from Greece, the beads could derive from a more ancient local productionascertained at the site of Frattesina (Rovigo, Italy) and dated to the Bronze Age.The aims of this study are: (i) to characterise a set of Iron Age glass artefacts, thus providing newquantitative chemical data; and (ii) to identify possible differences between finds recovered fromdifferent localities and between glass vessels and beads, in order to establish whether different manufactureswere active contemporaneously.The chemical analyses of major and minor elements were performed with an electron microprobe. Thenature of the opacifying and colouring agents was determined by X-ray diffraction. The sample set isrelatively homogeneous and most of the samples can be classified as low magnesium glass. The yellowopaque decorations are rich in Pb and Sb, while only Sb is present in the white and light blue samples.The XRD analyses confirmed the presence of lead antimonates in the yellow decorations and of calciumantimonates in the white and light blue decorations.

R. Arletti; G. Vezzalini; S. Benati; L. Mazzeo Saracino; A. Gamberini ( 2010 ) - ROMAN WINDOW GLASS: A COMPARISON AMONG FINDINGSFROM THREE DIFFERENT ITALIAN SITES - ARCHAEOMETRY - n. volume 52 - pp. da 252 a 271 ISSN: 0003-813X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Thirty-three samples of window glass and five glass lumps coming from three Italian archaeological sites - Suasa excavations (AN- Italy, settled from the 3rd century BC to the 5th - 6th cen AD), the Roman town Mevaniola (Forlì- Cesena, Italy) settled from the Imperial Age up to the 4th cen. AD) and heodoricVilla of Galeata (Forlì-Cesena- Italy, settled from the 6th cen. AD onwards) -were analysed to track the changes in the chemical composition and manufacturing technology of window glass through the centuries. Aims of this study are: i) to establish the origin of the raw materials; ii) to verify the chemicalhomogeneity among samples coming from different sites and/or produced with different techniques; iii) to sort the samples into the compositional groups of ancient glass. The analysis of all the chemical variables allowed two groups to be distinguished: a) finds from Mevaniola and Suasa and b) finds from Galeata. Allthe samples have the composition of the silica-soda-lime glass but, the analysis of minor elements, in particular of Fe, Mn, and Ti, makes it possible to split the samples into two groups, with the higher levels of these elements always found in the Galeata samples (HIMT glass). In conclusion, it can be asserted that the main differences between the samples are related to their chronology.

D. MALFERRARI; M.F. BRIGATTI; M.G. VEZZALINI; A. LAURORA ( 2010 ) - Water pollution reduction and water saving using a natural zeolitite cycle [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

GENERAL OBJECTIVES OF THE PROJECT 1)The protection of fresh and groundwater from nitrate pollution derived by agronomic industry. 2)The reduction of water and soil pollution derived by punctual (cattle breeding) and diffuse (agriculture) sources of nitrates. 3)The qualitative and quantitative preservation of the water resource. 4)The reduction and the prevention of pollution of seawater. 5)The optimization of the use of water in agriculture and a minor use of chemical fertilizers. 6)An improvement of agricultural soil characteristics. 7)The experimentation of a possible way to contrast desertification and agricultural soil exhaustion.

R. ARLETTI; C. GIACOBBE; S. QUARTIERI; G. SABATINO;G. TIGANO; M. TRISCARI; G. VEZZALINI ( 2010 ) - ARCHAEOMETRICAL INVESTIGATION OF SICILIANEARLY BYZANTINE GLASS: CHEMICAL ANDSPECTROSCOPIC DATA - ARCHAEOMETRY - n. volume 52 - pp. da 99 a 114 ISSN: 0003-813X [Articolo in rivista (262) - Articolo su rivista]
Abstract

A series of early Byzantine glasses, recovered in Ganzirri (Sicily, Italy), was analysed formajor, minor and trace elements. All the analysed fragments were found to be natron-basedsilica–lime glass. Concerning minor and trace elements, the samples can be divided into twogroups: glass with high Fe, Ti and Mn contents (HIMT glass) and glass with low levels ofFe, Ti and Mn. These results, strictly in agreement with literature data for glass of theMediterranean region, can be interpreted as a consequence of the wide trade networkestablished in this region and of the intense circulation of raw glass and artefacts fromdifferent Mediterranean areas. X-ray absorption spectroscopy studies at Fe and Mn K-edges,performed on HIMT glass, indicate that Fe is in the oxidized form while Mn is in the reducedform.

Montagna, Gabriele; Bigi, Simona; Kónya, P.; Szakáll, S.; Vezzalini, Maria Giovanna ( 2010 ) - CHABAZITE-MG: A NEW NATURAL ZEOLITE OF THE CHABAZITE SERIES. - AMERICAN MINERALOGIST - n. volume 95 - pp. da 939 a 945 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Chabazite-Mg, (Mg0.67K0.52Ca0.48Na0.08Sr0.03)Σ1.78[(Al3.16Si8.89)Σ12.05O24]·9.68H2O, is a new zeolite species of the chabazite series, occurring in basalts of the Karikás-tető area of Prága Hill, Veszprém County, Balaton Highland, Transdanubia, West Hungary. It crystallizes as single, colorless rhombohedra up to 0.4 mm in size. The streak is white and the luster is strong vitreous. Mohs’ hardness is about 4. The observed density is 1.98(1) g/cm3 and the calculated density is 1.964(7) g/cm3. Chabazite-Mg is anisotropic, uniaxial (+), ω = 1.465(5), ε = 1.469(5) (546 nm). In its chemical composition, a predominanceof Mg is observed among the extraframework cations. However, K and Ca are also very abundant, while Na and Sr levels are very low. The ratio Si/(Si+Al) is among the highest found in chabazite of hydrothermal genesis. Chabazite-Mg is rhombohedral, R3m space group, a = 9.3433(5) Å, α = 94.894(4)°. The six strongest X-ray lines measured in the powder pattern [d in Å (I) (hkl)] are: 9.306 (60) (100), 5.537 (37) (11 1), 4.958 (25) (111), 4.315 (100) (201), 2.924 (78) (31 1), 2.869 (41) (310). Single-crystal structure refinement of chabazite-Mg indicated that the extraframework occupation is distinct from other chabazite-series minerals. In particular, the Mg site (C3a) and one water site (W6a) are displaced from the threefold axis parallel to [111].

Arletti R.; Quartieri S.; Vezzalini G. ( 2010 ) - ELASTIC BEHAVIOR OF ZEOLITE BOGGSITE IN SILICON OIL AND AQUEOUS MEDIUM: A CASE OF HP-INDUCED OVER-HYDRATION - AMERICAN MINERALOGIST - n. volume 95 - pp. da 1247 a 1256 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

This paper reports the results of an in situ high-pressure synchrotron X-ray powder diffraction investigation on the natural zeolite boggsite [(K0.06Na0.36Sr0.01Ca7.00Mg1.20)(Al17.52Si78.62Fe0.05O192)·82.3 H2O]. The study was performed using both a (16:3:1) methanol:ethanol:water mixture (m.e.w.) as a nominally “penetrating” hydrostatic P-transmitting medium and silicon oil (s.o.) as a “non-penetrating” medium. The studied pressure ranges are: Pamb–7.6 and Pamb–5.9 GPa in m.e.w and s.o., respectively. No complete X-ray amorphization is observed up to the highest investigated pressures, and the original unit-cell parameters are almost completely recovered upon decompression in both media. The reductionsof a, b, c, and V, within the pressure-ranges investigated, are 5.3, 4.2, 4.0, and 13.0% in s.o. and 4.1, 4.1, 3.8, and 11.5% in m.e.w. The Rietveld structural refinements of the powder patterns of the experiments in m.e.w. converged successfully up to 3.6 GPa and demonstrated the penetration of 13 additional water molecules between 0.3 and 2.9 GPa. This over-hydration occurs without any unit-cell volume expansion and can be explained by the fact that no new extraframework sites arise during compression and that water penetration is the only factor to increase the occupancy of already existing sites. Boggsite compressibility is higher in s.o. than in m.e.w. In particular, compressibility in m.e.w. is lower below 3 GPa, whereas above this pressure, the P-V trend becomes similar in the two media. This can be ascribed to the fact that, during water molecule penetration (0.3 < P < 3 GPa), the effect of the P-transmitting medium is directed to compress the system as well as to penetrate the channels.

Cardarelli A.; Cannavò V; Levi S.T.; Lugli S.; Marchetti Dori S.; Vezzalini M.G.; ( 2009 ) - Bronze Age Raw Materials: ana Analytical and Experimental Approach ( Micro et Nano: Scientiae Mare Magnum - - 14-20 giugno 2009) ( - 14th Int. Clay Conference ) (Vanzi Bari ITA ) - n. volume I [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Archeometrical analyses of Bronze Age pottery from Modena area

Ori S.; Mazzucato E.; Vezzalini G. ( 2009 ) - Dehydration dynamics of barrerite: an in-situ synchrotron XRPD study. - AMERICAN MINERALOGIST - n. volume 94 - pp. da 64 a 73 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thermally induced structural modifications of the natural zeolite barrerite [Na16Al16Si56O144·52H2O, a = 13.6239(4) Å, b = 18.2033(5) Å, c = 17.8317(7) Å, V = 4422.3(3) Å3, space group Amma, framework type STI] were studied in a temperature-resolved X-ray powder diffraction experiment, using synchrotron radiation, in the temperature range 339–973 K. In the initial stage of heating, up to 508 K, barrerite Phase A (space group Amma) is stable, the unit-cell volume decreases by about 4% and a water release of about 66% is observed. Between 521 and 598 K, a phase transition to the collapsed so-called barrerite Phase B (space group Amma) is observed. During the transition, the rotation of the 4254 secondary building units causes a large decrease in cell volume and deformation of the channel system. Phase B, at 611 K, shows the statistical breaking of T-O-T bridges in the 4-rings and the migration of the involved tetrahedral atoms to new “face-sharing” tetrahedra, with a consequent reduction of the free volume of the channels parallel to [100]. The new structure is stable up to 741 K and the total volume decrease is about 16%. A new phase appears from 754 K with cell parameters similar to those reported for the highly deformed barrerite Phase D and is stable up to 910 K, which is the temperature at which the total volume decrease is 22.5%. The material does not undergo amorphization up to the highest temperature investigated.

R. Arletti; G. Vezzalini; S. Quartieri; D. Ferrari ( 2009 ) - Polichrome glass of VII VI century BC: Etruscan and Phoenician context in comparison ( Riflessioni e trasparenze. diagnosi e conservazione di opere e manufatti vetrosi. - - 24-26 febbraio 2009) ( - Riflessioni e trasparenze. diagnosi e conservazione di opere e manufatti vetrosi. ) (Patron Editore Bologna ITA ) - n. volume 1 - pp. da 24 a 26 ISBN: 9788855530859 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

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R. Arletti; G. Vezzalini; S. Quartieri; D. Ferrari ( 2009 ) - Polychrome glass from etruscan contexts in Northern Italy: chimica and mineralogical data ( 37th International Symposium on Archaeometry - - may 12-16, 2008) ( - ISA 2008 ) (Tipografia senese Siena ITA ) - n. volume - - pp. da 81 a 81 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

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Carpenito G.; Corradini L.; Levi S.T.; Vezzalini G. ( 2009 ) - Impasto “fine, semifine o grossolano”? Terminologia archeologica e classificazione archeometrica ( Le classi ceramiche: situazione degli studi, Atti della 10° Giornata di Giornata di Archeometria della Ceramica - - 2006) ( - Le classi ceramiche: situazione degli studi, Atti della 10° Giornata di Giornata di Archeometria della Ceramica ) (Edipuglia Bari ITA ) - pp. da 33 a 45 ISBN: 9788872285671 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Analisi petrografica associata a analisi di immagine per misurare la granulometria dei componenti dell'impasto di ceramiche protostoriche e discutere i criteri di classificazione archeologica e archeometrica

ARLETTI R; QUARTIERI S; SABATINO G; TRISCARI M; VEZZALINI G; GIACOBBE C; TIGANO G ( 2009 ) - Sicilian early Bizantine glass finds: from analytical data to trade informations. ( - Annales of the 17th AIHV Congress, Antwerp. ) (Academic and Scientific Publishers, Brussels Brussels BEL ) - pp. da 546 a 551 ISBN: 978 90 5487 618 2 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

The Ganzirri glass finds can be classified, on the basis of the CaO/Al2O3 ratio, as Levantine I. Moreover, both minor and trace element data allows us to discriminate two distinct groups, one of which is composed of typical HIMT glass. The co-presence of these two glass types is reported for several localities of the Mediterranean area in Byzantine times, and, in particular, the REE and trace elements patterns of the Ganzirri samples are extremely similar to those found for Cyprus finds. Our results confirm that the glass artefacts found in both localities were produced with different glass batches, made with distinct coastal sands. This conclusion is not surprising when considering the strategic position of both sites for trading in the Mediterranean region.

Ori S; Vezzalini G; Galli E ( 2009 ) - Thermal induced structural modifications of the high silica zeolite Gottardiite: an in-situ XRPD study - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 126 - pp. da 171 a 181 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thermally induced structural modifications of the natural zeolite gottardiite ((Na0.78K0.24Mg3.51Ca4.11Sr0.06Ba0.05)(Fe0.14Al17.47Si118.70O272) · 92.33 H2O, a = 13.631(1), b = 25.047(3) and c = 22.586(3) Å, V = 7711(1) Å3, s.g. Cmca, framework type NES) were studied in the temperature range 308 - 1203 K in a temperature-resolved X-ray powder diffraction experiment, using synchrotron radiation. The unit cell parameters were refined in the whole temperature range, while structural refinements were performed approximately every 100 K, at 308 K, 371 K, 475 K, 580 K, 674 K, 779 K, 873 K, and 978 K. No signs of phase transitions were observed in the whole investigated T-range and up to the highest temperature the material does not undergo amorphization. Gottardiite shows a high thermal stability, as a consequence of the high Si content, and an extremely rigid structure with a substantial absence of cell volume change. The framework deformation induced by dehydration involves only a slight distortion of the 10-ring and 12-ring channels running in the a and b directions. From room temperature to 580 K gottardiite looses water quite slowly and regularly. The main water loss is observed in the temperature range 580 - 779 K. Above this temperature gottardiite again dehydrates slowly, and at 978 K about 13 water molecules remain.

ARLETTI R.; VEZZALINI G.; MAZZEO SARACINO M.L; GAMBERINI A. ( 2008 ) - Roman and late-roman window glass from three Italian sites: chemical and morphological data in comparison ( ISA 2008 - - may 12-16, 2008) ( - 37th International Symposium on Archaeometry, ) (- Siena ITA ) - n. volume - - pp. da 125 a 125 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

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E. FOIS; A. GAMBA; G. TABACCHI; S. QUARTIERI; S. ORI;G. VEZZALINI ( 2008 ) - HP-induced over-hydration and water ordering in gismondine ( OXIDES 2008 - - 14-18 luglio, 2008) ( - IV International Workshop OXIDE BASED MATERIALS novelties and perspectives ) (- Como ITA ) - n. volume - - pp. da 77 a 77 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

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ORI S; QUARTIERI S; VEZZALINI G; DMITRIEV V ( 2008 ) - Pressure-induced structural deformation and elastic behavior of wairakite (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 93 - pp. da 53 a 62 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The elastic behavior and the high-pressure structural evolution of the zeolite wairakite [ideal chemical formula Ca(Al2Si4O12)⋅2H2O, space group I2/a], the Ca-analog of analcime, have been investigated by means of in-situ synchrotron X-ray powder diffraction from ambient pressure to 7.8 GPa, and upon decompression. No complete X-ray amorphization is observed up to the highest investigated pressure, and the original unit-cell parameters are recovered upon decompression. The Rietveld structural refinements of the powder patterns converged successfully up to 2.5 GPa; above this pressure, a phase transition to triclinic symmetry is observed and only the unit-cell parameters were refined. An overall reduction of about 14% of the unit-cell volume between 0.0001 and 7.0 GPa is observed, demonstrating that wairakite is much more flexible upon compression than upon heating. The pressure dependence of the cell parameters is strongly anisotropic and larger after the transition to the triclinic space group. The elastic parameters refined with a second-order Birch-Murnaghan Equation of State are V0 = 2536(4) Å3, K0 = 39(3) GPa, and V0 = 2632(38) Å3, K0 = 24(3) GPa, for the monoclinic and triclinic phases, respectively.The structure distortion of monoclinic wairakite, proceeding via tetrahedral tilting, induces deformationsin the 4-, 6-, and 8-membered rings and an increase in the extra-framework Ca coordination number.A comparative discussion of the compressibility behavior of wairakite and analcime is reported.

LEVI S.T; CANNAVÒ V; LUGLI, S; MARCHETTI DORI S; VEZZALINI MARIA GIOVANNA ( 2008 ) - Pottery production in the Po valley during the Bronze age: an archaeometrical approach to the terramare society ( ISA 2008 - - may 12-16, 2008) ( - 37th International Symposium on Archaeometry ) (- Siena ITA ) - n. volume 1 - pp. da 161 a 161 ISBN: - ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

During the Bronze Age the Po valley was occupied by fortified villages (1650-1170 BC) which were linked by a common culture (Terramare). Their society had a complex structure and was among the most advanced in Europe. The pottery analysis project is oriented to investigate the specialization of the manufacturing process in the frame of the social organization in the Terramare. 180 pots from several sites near Modena (Pontenuovo, Gorzano, Cà dei Monesi, Montebarello and Montale), dated between Middle and Recent Bronze Age, have been analysed. 30 clays and other sediments have been sampled from different local geological units (Cardarelli et al. 2007). Ceramic and sediment samples have been investigated by: granulometry, petrography with digital image process, chemical analysis of major, minor and trace elements (WDS-XRF), X-ray powder diffraction. Some XRPD experiments were performed on raw and physico-chemical treated sediment samples (air dried, glycolated, heated at 375 and 550 °C oriented mounts) to obtain the clay minerals composition. The ceramic paste is coarse, with abundant temper (mainly calcite and grog). The common mineral composition is: quartz, albite, k-feldspar, illite (muscovite). Amphiboles, pyroxene, calcite, rutile, forsterite, hematite are present only in some samples. Chemical compositions of the pottery are quite homogenous. For the sediments the concentration of CaO is an important marker to distinguish the raw materials used for the pottery. The pots are mainly locally made, using different locals raw materials, with some differences in each site and in the selection of temper according to the functions of the pots. In the frame of this research an experimental archaeological activity has been performed in the archaeological park of Montale. Bronze Age pottery was reproduced with compatible raw materials and ancient manufacturing techniques (coils and moulds). Time and difficulty for the reproduction of each pot has been recorded and 6 different groups of pots, corresponding to increasing degrees of specialization, have been identified (Brodà et al. in press).

Fois E.; Gamba A.; Medici C.; Tabacchi G.; Quartieri S.; Mazzucato E.; Arletti R.; Vezzalini G. ( 2008 ) - High pressure deformation mechanism of Li-ABW: sinchrotron XRPD study and ab initio molecular dynamics simulations. - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 115 - pp. da 3267 a 3280 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The response to compression of the synthetic zeolite Li-ABW (LiAlSiO4 H2O, Z = 4, s.g. Pna21) was explored by synchrotron X-ray powder diffraction experiments, using silicone oil as non-penetrating pressure transmitting medium, and Car Parrinello Molecular Dynamics simulations. In the range Pamb – 8.9 GPa, a nearly isotropic compression for the axial parameters and a cell volume decrease of approximately 12% are observed. A discontinuity in the cell parameters vs P behaviour can be detected between 5 and 6 GPa. As a consequence, the bulk modulus was calculated separately in the Pamb – 4.9 GPa and 5.6–8.9 GPa pressure ranges. The corresponding values (72(2) GPa and 80(2) GPa, respectively) are among the highest found up to now for zeolites studied with non-penetrating P-transmittingmedia. Molecular Dynamics simulations were performed at volumes corresponding to Pamb, 1.5, 5.6, and 7.6 GPa, respectively.At 1.5 GPa the channel system is already elliptically deformed, and the zig-zag trend of the 4-ring tetrahedral chains is enhanced. Moreover, the water molecule chain running along the channel becomes interrupted and the water molecules are more strongly connected to the framework oxygen atoms. The four-fold coordination of Li cation is maintained up to the highest pressure and only a slight bond distance decrease is observed above 1.5 GPa. In the Pamb – 5.6 GPa range, all T–O–T angles decrease with pressure, and hence the Li-ABW structure can be defined as collapsible. Otherwise, at higher compression, average T–O–T angles increase slightly. Overall, the deformation of the Li-ABW upon compression resembles that achieved by anhydrous Li-ABW in the high temperature regimes.

Triscari M.; Quartieri S.; Sabatino G.; Vezzalini G.; Arletti R.; Mastelloni M.A. ( 2008 ) - Analisi archeometrica di tessere musive in pasta vitrea da un pavimento di Lipari. ( - Archeologia a Messina. Studi su materiali preistorici, arcaici, ellenistici e romani del museo ) (Laruffa Editore srl Reggio Calabria ITA ) - n. volume 11 - pp. da 153 a 157 ISBN: 9788861640177 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

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ARLETTI R.; VEZZALINI G.; BIAGGIO SIMONA S.; MASELLI SCOTTI F. ( 2008 ) - ARCHAEOMETRICAL STUDIES OF ROMAN IMPERIAL AGE GLASS FROM CANTON TICINO. (Primo editore: University of Oxford. Research Laboratory for Archaeology and the History of Art, oxford editore attuale: Blackwell Publishing Limited:9600 Garsington Road, Oxford OX4 2DQ United Kingdom:011 44 1865 776868 , (781)388-8200, EMAIL: agentservices@oxon.blackwellpublishing.com, e-help@blackwellpublishers.co.uk, INTERNET: http://www.blackwellpublishing.com, Fax: 011 44 1865 714591 ) - ARCHAEOMETRY - n. volume 50 - pp. da 606 a 626 ISSN: 0003-813X [Articolo in rivista (262) - Articolo su rivista]
Abstract

An archaeometrical study of Roman glass finds recovered in the Canton Ticino area was performed after the finding of traces of possible glass-working at Muralto near Locarno. The aim of this work is to provide chemical characterization of these glass varieties—never analysed before—and to compare the results obtained with those for glass of the same period coming from other sites (Aquileia, Augusta Praetoria and Modena). The chemical data shows that the composition of Canton Ticino glass remained the same from the first to the fourth century AD. Moreover, the large amounts of Sb used as a decolouring agent in these samples represents a peculiar trait.

R. ARLETTI; S. QUARTIERI; G. VEZZALINI; G. SABATINO; M. TRISCARI; M. A. MASTELLONI ( 2008 ) - ARCHAEOMETRICAL ANALYSES OF GLASS CAKES AND VITREOUS MOSAIC TESSERAE FROM MESSINA (SICILY, ITALY) (Elsevier BV:PO Box 211, 1000 AE Amsterdam Netherlands:011 31 20 4853757, 011 31 20 4853642, 011 31 20 4853641, EMAIL: nlinfo-f@elsevier.nl, INTERNET: http://www.elsevier.nl, Fax: 011 31 20 4853598 ) - JOURNAL OF NON-CRYSTALLINE SOLIDS - n. volume 354 - pp. da 4962 a 4969 ISSN: 0022-3093 [Articolo in rivista (262) - Articolo su rivista]
Abstract

We report the results of a study performed on several glass samples recovered after the destructioncaused in Messina by the earthquake of 1908, and stored in the ‘Fiore’ deposit of the Regional Museumof Messina (Italy). The samples, still lacking a reliable classification, are glass cakes, some spare mosaictesserae, and fragments of a well-dated mosaic (Mosaico dell’Angelo, XIII–XIV century A.D.). EPMA,SEM-EDS, XRPD and XAS were employed to provide a detailed chemical, mineralogical and spectroscopiccharacterization of the samples. The chemical analyses of major elements show high levels of K2O andMgO, as a result of the prevalent use of plant ashes as flux. The cakes are characterized by a large dispersionof Si, Al and Ca contents, suggesting the use of different starting raw materials. The most commoncrystalline phases used as opacifiers and colorants are quartz and wollastonite. Crystalline aggregates ofSnO2 are present in the gray cakes, whereas PbSnO3 crystals are found in two green mosaic tesserae. Allthe red samples contain small clusters of metallic copper. On the basis of the chemical composition, it ispossible to confirm that most of the samples were produced in the XIII–XIV century, while no specificconclusions were reached on the possible use of the glass cakes as raw glass materials for the productionof the investigated mosaic tesserae.

ARLETTI R; VEZZALINI G; QUARTIERI S; FERRARI D; MERLINI M; AND COTTE M ( 2008 ) - Polychrome etruscan glass: FIRST NON-DESTRUCTIVE CHARACTERISATION WITH SYNCHROTRON mXRF, mXANES and XRPD. (Springer Verlag Germany:Tiergartenstrasse 17, D 69121 Heidelberg Germany:011 49 6221 3450, EMAIL: g.braun@springer.de, INTERNET: http://www.springer.de, Fax: 011 49 6221 345229 ) - APPLIED PHYSICS. A, MATERIALS SCIENCE & PROCESSING - n. volume 92 - pp. da 127 a 135 ISSN: 0947-8396 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work is devoted to the characterization ofa suite of very rare, highly decorated and coloured glass vesselsand beads from the VII to the IV century BC. The most seriousdifficulty in developing this study was that any sampling –even micro-sampling – was absolutely forbidden. As a consequence,themineralogical and chemical nature of chromophoresand opacifiers present in these Iron Age finds were identifiedby means of the following synchrotron-based, strictly nondestructive,techniques: micro X-ray fluorescence (μ-XRF),FeK-edge micro X-ray absorption near edge spectroscopy (μ-XANES) and X-ray powder diffraction (XRPD). The μ-XRFmapping evidenced high levels of Pb and Sb in the yellow decorationsand the presence of only Sb in the white and light-blueones. Purple and black glass show high amounts of Mn andFe, respectively. The XRPD analyses confirmed the presenceof lead and calcium antimonates in yellow, turquoise and whitedecorations. FeK-edge μ-XANES spectra were collected in differentcoloured parts of the finds, thus enabling the mapping ofthe oxidation state of these elements across the samples. In mostof the samples iron is present in the reduced form Fe2+ in thebulk glass of the vessels, and in the oxidized form Fe3+ in thedecorations, indicating that these glass artefacts were producedin at least two distinct processing steps under different furnaceconditions.

Montagna G.; Arletti R.; Vezzalini G.; Quartieri S. ( 2008 ) - HP- induced deformation effects in MFI-type zeolite ( Iv International Workshop Oxide Based Materials, Novelties and Prespectives - - July 6-10, 2008) ( - Oxide Based Materials, Novelties and Prespectives ) (Gamba, E., Fois, E., Tabacchi, G. Como ITA ) - n. volume - - pp. da 119 a 120 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

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G. Vezzalini ( 2008 ) - Pressure-induced over-hydration of zeolites: a review and new insights from gismondine ( 1st SIMP-AIC Joint Meeting. - - 7-12 September 2008) ( - Learning from and for the Planet Earth. Structures and models in Earth, Materials and Life Sciences. ) (Mediaprint Srl Livorno ITA ) - n. volume - - pp. da 169 a 169 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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R. Arletti; M. Vandini; C. Fiori; G. Vezzalini ( 2008 ) - Eleventh century Byzantine mosaic tesserae from the Greek monasteries of Daphni and Hosios Loukas ( 1st SIMP-AIC Joint Meeting. - - 7-12 September 2008.) ( - Learning from and for the Planet Earth. Structures and models in Earth, Materials and Life Sciences ) (Mediaprint Srl Livorno ITA ) - n. volume - - pp. da 135 a 135 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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Fiori C.; Vandini M.; Arletti R.; De Giorgi R.; Vezzalini G. ( 2008 ) - Vetro musivo romano della fine del XVI secolo. - C+CA - n. volume 2 - pp. da 121 a 129 ISSN: 1970-0393 [Articolo in rivista (262) - Articolo su rivista]
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Ori S.; Quartieri S.; Vezzalini G.; Dmitriev V. ( 2008 ) - Pressure-induced over-hydration and water ordering in gismondine: a synchrotron powder diffraction study. - AMERICAN MINERALOGIST - n. volume 93 - pp. da 1393 a 1403 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

This paper reports the results of an in situ HP synchrotron X-ray powder diffraction investigation on the natural zeolite gismondine (ideal chemical formula Ca4Al8Si8O32·16H2O, space group P21/c). The study was performed from Pamb to 7.9 GPa, and upon decompression, using methanol:ethanol:water (16:3:1) mixture (m.e.w.) as a nominally penetrating hydrostatic P-transmitting medium. No complete X-ray amorphization is observed up to the highest investigated pressure, and the original unit-cell parameters are almost completely recovered upon decompression. From 0.6 GPa, the water content is slightly higher than at ambient pressure, as a result of a moderate over-hydration. Moreover, at about 2 GPa, a significant water molecule system re-arrangement occurs, characterized by an ordering of part of the water molecules from four partially occupied sites to only two fully occupied ones. The over-hydration, but not the water ordering, is substantially irreversible upon pressure release. The Rietveldstructural refinements of the powder patterns converged successfully up to 2.8 GPa; above this pressure, a phase transition to triclinic symmetry was observed and only the unit-cell parameters were refined. The comparison of the overall cell volume reductions and of the bulk modula of gismondine compressed between Pamb and 7.9 GPa in m.e.w. and in silicone oil, reveals that this is the unique zeolite with a higher compressibility in penetrating vs. non-penetrating P-transmitting media. This is ascribed to the re-organization of the water molecule system upon compression in m.e.w., which leaves a larger free volume inside the pores with respect to the phase compressed in silicone oil.

ARLETTI R.; VEZZALINI G.; QUARTIERI S.; MALNATI L.; FERRARI D.; DACAPITO F.; MERLINI M. COTTE M. ( 2007 ) - Colouring and opacifying agents in polycrome etruscan glass: archaeometric data from synchrotron μXRF, μXANES and XRPD. ( AIAR 2007 - - 28/02-2/03) ( - AIAr 2007 “Colore e arte storia e tecnologia del colore nei secoli” Firenze 28 febbraio-2 marzo 2007. ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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QUARTIERI S.; ORI S.; VEZZALINI G.; DMITRIEV V. ( 2007 ) - HP-INDUCED STRUCTURAL DEFORMATIONS AND ELASTIC BEHAVIOR OF WAIRAKITE ( Frontiers in Mineral Sciences 2007 - - 26-28 june 2007) ( - Frontiers in Mineral Sciences 2007. ) (- cambridge GBR ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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M. TRISCARI; S. QUARTIERI; G. SABATINO; G. VEZZALINI; M.A. MASTELLONI; F. SANTALUCIA ( 2007 ) - Caratterizzazione chimica e spettroscopica di tessere musive in pasta vitrea da siti archeologici siciliani. ( - “Tecniche di analisi di materiali nei Beni Culturali”. ) (Carbone Editore PALERMO ITA ) - n. volume - - pp. da 110 a 114 ISBN: 9788888803296 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
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CARDARELLI A.; CARPENITO G. ; LEVI S.T. ; LUGLI S. ; MARCHETTI DORI S. ; VEZZALINI G. ( 2007 ) - ARCHAEOMETRICAL INVESTIGATIONS OF IMPASTO POTTERY FROMTERRAMARA OF GORZANO (MODENA, ITALY) ( - Archaeometric and Archaeological Approaches to Ceramics, BAR International series ) (Archaeopress Oxford GBR ) - n. volume 1691 - pp. da 69 a 74 ISBN: 9781407301297 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Bronze Age Impasto pottery from Gorzano Terramarawas analysed to identify raw materials and manufacturingtechniques. Impasto ceramic paste is a heterogeneousmixture of fine sediments and tempers. Ceramics andsediments surrounding the site were characterised throughpetrographic analysis, chemical analysis of major, minorand trace elements and X-ray powder diffraction. Theresults show that the fine fraction of the pottery is lowin carbonates, while most sediments are calcareous andshow different clay mineral/carbonate ratios. Only threesediment samples of the Niviano unit are chemically andmineralogically similar to the fine fraction of the pottery.However the higher concentration of Al2O3 in the potterysuggests the use of a raw material richer in clay mineralsand hence the possibility that sediment from the Nivianounit were partially levigated before use.

CARDARELLI A; CARPENITO G; S. LEVI; LUGLI S; MARCHETTI DORI S; VEZZALINI M.G. ( 2007 ) - Archaeometrical investigations of Impasto pottery from Terramara of Gorzano (Modena, Italy) ( EMAC ‘05 8th European Meeting on Ancient Ceramics - - 2005) ( - Archaeometric and Archaeological Approaches to Ceramic ) (Archaeopress OXFORD GBR ) - n. volume BAR I.S. 1691 - pp. da 69 a 74 ISBN: 9781407301297 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Bronze Age Impasto pottery from Gorzano Terramara was analysed to identify raw materials and manufacturing techniques. Impasto ceramic paste is a heterogeneous mixture of fine sediments and tempers. Ceramics and sediments surrounding the site were characterised through petrographic analysis, chemical analysis of major, minor and trace elements and X-ray powder diffraction. The results show that the fine fraction of the pottery is low in carbonates, while most sediments are calcareous and show different clay mineral/carbonate ratios. Only three sediment samples of the Niviano unit are chemically and mineralogically similar to the fine fraction of the pottery. However the higher concentration of Al2O3 in the pottery suggests the use of a raw material richer in clay minerals and hence the possibility that sediment from the Niviano unit were partially levigated before use.

SABATINO M.; VEZZALINI G.; ARLETTI R; MASTELLONI M.A QUARTIERI S.; SANTALUCIA F.; TRISCARI M.; ( 2007 ) - I colori di Piazza Armerina; caratterizzazione chimico-fisica di tessere in pasta vitrea. ( AIAR 2007 - - 28/02-2/03) ( - AIAr 2007 “Colore e arte storia e tecnologia del colore nei secoli” Firenze 28 febbraio-2 marzo 2007. ) (- Firenze ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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FIORI C.; VANDINI M.; ARLETTI R.; VEZZALINI G. ( 2007 ) - Produzione di vetro colorato per mosaico nella prima e tarda epoca bizantina. ( AIA 2007 - - 28/02-2/03) ( - AIAr 2007 “Colore e arte storia e tecnologia del colore nei secoli” Firenze 28 febbraio-2 marzo 2007. ) (- Firenze ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R; VEZZALINI G; QUARTIERI S; FERRARI D; MERLINI M; COTTE M ( 2007 ) - Polychrome Etruscan glass: a non destructive study by μXRF, μXANES and XRPD. ( 24th European Crystallographic Meeting - - 22-27 august 2007) ( - 24th European Crystallographic Meeting, Marrakech, Morocco, 22-27 August 2007 ) - ACTA CRYSTALLOGRAPHICA. SECTION A - n. volume A63 - pp. da 106 a 106 ISBN: 978 ISSN: 1600-5724 [Abstract in rivista (266) - Abstract in Rivista]
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ORI S.; VEZZALINI G.; QUARTIERI S.; DMITRIEV V. ( 2007 ) - Pressure induced deformations and elastic behaviour of wairakite ( 24th European Crystallographic Meeting - - 22-27 august 2007) ( - 24th European Crystallographic Meeting, Marrakech, Morocco, 22-27 August 2007 ) (- Marrakech MAR ) - n. volume - - pp. da 269 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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C. BETTI; E. FOIS; E. MAZZUCCATO; C. MEDICI; S. QUARTIERI; G. TABACCHI; G. VEZZALINI; V. DMITRIEV ( 2007 ) - GISMONDINE UNDER HP: DEFORMATION MECHANISM AND RE-ORGANIZATION OF THE EXTRA-FRAMEWORK SPECIES. (Elsevier Science Incorporated / NY Journals:Madison Square Station, PO Box 882:New York, NY 10159:(212)633-3730, EMAIL: usinfo-f@elsevier.com, INTERNET: http://www.elsevier.com, Fax: (212)633-3680 ) - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 103 - pp. da 190 a 209 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The response to compression of the zeolite gismondine, which is the natural counterpart of the synthetic zeolite P, was explored by synchrotron X-ray powder diffraction experiments with a non penetrating pressure transmitting medium and by Car Parrinellomolecular dynamics simulations. In the range Pamb-7.4 GPa, no pressure-induced amorphization occurs and the cell volume decrease is approximately 8%. The corresponding bulk modulus (K0 = 63.8(2) GPa) is one of the highest found to date forzeolites studied under the same conditions. The pressure-induced cell modifications arefound to be reversible upon decompression up to about 4 GPa. Gismondine is found tobe more compressible along a and c with respect to b, and shows a tendency from monoclinicity towards tetragonality with increasing pressure. The results of the Molecular Dynamics simulations made it possible to rationalize at the microscopic levelthe slope variation observed in the volume-pressure curve and to explain the role of the framework and extraframework atoms in the deformation mechanism. Upon compression, the Ca coordination number increases and the water molecules organizethemselves in a different supra-molecular arrangement. Interestingly the pressure induced deformation mechanism described here is similar to that found in gismondineupon dehydration under vacuum.

ARLETTI R.; CIARALLO A.; QUARTIERI S.; SABATINO G.; VEZZALINI G. ( 2006 ) - Archaeometrical Analyses of Game counters from Pompeii. ( - Geomaterials in Cultural Heritages ) (The Geological Society LONDON GBR ) - n. volume 257 - pp. da 175 a 186 ISBN: 9781862391956 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Among the glass finds of the Pompeii excavations, numerous objects of opaque and transparent glassy material of different colours were recovered and classified as game counters. The main aims of this work were to characterize these samples so as to identify the materials used as colorants and opacifying agents, and subsequently to deduce the technology used for their production. The results of the chemical and mineralogical analysesobtained for game counters were also compared with those obtained for transparent and opaque glass artefacts. The chemical analyses were carried out, using only 300 mg ofsample, by both wavelength-dispersive electron microprobe and X-ray fluorescence analysis. The crystalline phases present in the opaque glass were identified using both an automatic X-ray powder diffractometer and a Gandolfi camera. Secondary and backscattered electron images were obtained to study the distribution and morphology of the opacifier particles, and qualitative chemical analyses were obtained with an energy-dispersive system. All the game counters analysed can be classified as silica–soda–lime glass. Two calcium antimonates (CaSb2O6 and Ca2Sb2O7) were identified in the opaque white, green and blue glass, and Pb2Sb2O7 particles were detected in the opaque yellow glass. Particles of metallic copper were detected by both energy-dispersive system and X-ray powder diffraction. These results support the hypothesis that transparent game counters were obtained by remelting of fragments of common transparent artefacts. In contrast, opaque finds wereprobably produced using the glassy paste employed in the production of mosaic tesserae.

ARLETTI R.; MAZZUCATO E.; VEZZALINI G. ( 2006 ) - Influence of dehydration kinetics on T-O-T bridge breaking in zeolites with framework type STI: the case of stellerite. (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 91 - pp. da 628 a 634 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thermally induced structural modifications of the natural zeolite stellerite [Ca8Al16Si56O144·58H2O, a = 13.5947(4), b = 18.1823(6), and c = 17.8335(6) Å, V = 4408.1(3) Å3, space group Fmmm, framework type STI] were studied in a temperature-resolved X-ray powder diffraction experiment, usingsynchrotron radiation, in the temperature range RT-976 K. In the initial stage of heating (below 430 K) Stellerite Phase A (space group Fmmm) is stable, and the cell volume decreases only 0.6% to thistemperature. Between 430 and 490 K most of the water is released, the symmetry lowers, and a phase transition to the collapsed so-called Phase B (space group Amma) is observed. In this phase rotation of the 4254 Secondary Building Units causes cell volume contraction and deformation of the channelsystem. This new phase, at 530 K, shows the statistical breaking of T-O-T bridges in the four-rings and the migration of tetrahedral atoms to new “face-sharing” tetrahedra, which partially occlude boththe channels parallel to [100] and to [001]. This framework deformation is interpreted as due to the strain induced by calcium atoms on the framework to achieve better coordination after the release of water. The new structure is stable up to 750 K and the total volume decrease is about 8%. The dehydration process causes a similar framework deformation and the transition to a collapsed phase characterized by the statistical breaking of T-O-T bridges in all zeolites with STI-type frameworks.However, comparing the results obtained with different thermal kinetics, it is possible to assume that the experimental conditions play a primary role in the mechanisms of dehydration and of framework bridge breaking.

ARLETTI R.; QUARTIERI S.; SABATINO G.; TIGANO G.; TRISCARI M.; VEZZALINI G.; GIACOBBE C. ( 2006 ) - Sicilian Early Bizantine glass finds: from analytical data to production and trade information ( AIHV 2006 - - 4-8 september) ( - XVII Congress Of Association Internazionale Hystoire du Verre, Antwerp, Belgium, September, 4-8 2006. ) (- - BEL ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R.; QUARTIERI S.; SABATINO G.; TRISCARI M.; VEZZALINI G.; MASTELLONI M.A. ( 2006 ) - Glass cakes and mosaic tesserae from Messina (Sicily): an archaeometrical study. ( AIHV 2006 - - 4-8 september) ( - , XVII Congress of Association Internazionale Hystoire du Verre, Antwerp, Belgium,September, 4-8 2006 ) (- Antwerp BEL ) - n. volume - - pp. da 191 a 191 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R.; VEZZALINI G.; QUARTIERI S.; MALNATI L.; FERRARI D.; DACAPITO F.; MERLINI M.; COTTE M. ( 2006 ) - Polycrome Etruscan glass: first archaeometric data from synchrotron mXRF, mXANES and XRPD ( SILS 2006 - - 6-8 luglio 2006) ( - XIV Congresso Societa’ Italiana Luce di Sincrotrone, Napoli, Italy, July, 6-8 2006 ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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FIORI C.; VANDINI M.; ARLETTI R.; VEZZALINI G. ( 2006 ) - Analisi Archeometriche di vetri musivi tardo-bizantini dal monastero di Dafni (Grecia) ( AIAR 2006 - - 1-3 febbraio 2006) ( - IV congresso Nazionale di Archeometrica, Scienza e beni culturali, Pisa, Italy, Febbraio 1-3 2006 ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R; MASTELLONI M. A.; QUARTIERI S.; SABATINO G.; TRISCARI M.; VEZZALINI G. ( 2006 ) - Analisi Archeometriche di Pani di vetro e tessere musive siciliane di epoca bizantina ( AIAR 2006 - - 1-3 febbraio) ( - IV Congresso Nazionale di Archeometrica, Scienza e beni culturali, Pisa, 1-3 Febbraio 2006 ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ORI S.; QUARTIERI S.; VEZZALINI G. ( 2006 ) - Wairakite under HP: elastic behavior and structural deformations. ( ELETTRA USERS’ MEETING - - 20-22 novembre) ( - ELETTRA USERS’ MEETING, WORKSHOP ON "SCIENCE AT HIGH PRESSURES", Trieste 20-22/11/2006. ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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QUARTIERI S.; VEZZALINI, M.G.; BETTI M.C.; FOIS E.; TABACCHI G. ( 2006 ) - Gismondine under HP: deformation mechanism and reorganization of the extra-framework species. ( 19TH GENERAL MEETING OF THE INTERANTIONAL MINERALOGICAL ASSOCIATION - - 23-28/07/2006) ( - 19TH GENERAL MEETING OF THE INTERANTIONAL MINERALOGICAL ASSOCIATION. 23-28/7/2006 ) (- Kobe JPN ) - n. volume - - pp. da 162 a 162 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ORI S.; MAZZUCCATO E.; VEZZALINI G. ( 2006 ) - Dinamica di disidratazione della zeolite barrerite: studio XRPD in-situ in luce di sincrotrone ( SIMP 2006 - - 27-30 settembre 2006) ( - 85° CONGRESSO SIMP Fluminimaggiore, 27-30 settembre 2006. ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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QUARTIERI S; MEDICI C; M. VEZZALINI; BETTI M.C; FOIS E. TABACCHI G ( 2006 ) - Compressibilità e deformazione strutturale della zeolite gismondina: un approccio combinato XRPD e dinamica molecolare ab-initio. ( SIMP 2006 - - 27-30 settembre 2006) ( - 85° CONGRESSO SIMP Fluminimaggiore, 27-30 settembre 2006. ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ORI S.; MAZZUCCATO E.; VEZZALINI G. ( 2006 ) - Dehydration dynamics of barrerite: an in-situ synchrotron XRPD study ( AIZ 2006 - - 31 august-2 september 2006) ( - AIZ Day and AIZ workshop 2006: Innovative applications of layered materials: from catalysis to nanotechnology. ) (- alessandria ITA ) - n. volume - - pp. da 289 a 290 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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CARPENITO G.; LEVI S.T.; VEZZALINI G. ( 2006 ) - Impasto “fine, semifine, grossolano?” Classificazione archeologica e valutazione archeometrica. ( 10a giornata di archeometria della ceramica. - - 5-7 Aprile 2006) ( - 10a giornata di archeometria della ceramica. Roma, 5-7 Aprile 2006. ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R.; DALCONI M.C.; QUARTIERI S.; TRISCARI M; VEZZALINI G. ( 2006 ) - Roman coloured and opaque glass: a chemical and spectroscopic study (Springer Verlag Germany:Tiergartenstrasse 17, D 69121 Heidelberg Germany:011 49 6221 3450, EMAIL: g.braun@springer.de, INTERNET: http://www.springer.de, Fax: 011 49 6221 345229 ) - APPLIED PHYSICS. A, MATERIALS SCIENCE & PROCESSING - n. volume A83 - pp. da 239 a 245 ISSN: 0947-8396 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work reports the results of an archaeometrical investigation of opaque Roman glass and is mainly focussed on the role of configuration and oxidation state of copper on the colour and opacity of red and green opaque finds (mosaic tesserae, game counters, and glass artefacts) from Sicily and Pompeii excavations. The glass fragments were characterisedby EMPA, SEM-EDS, TEM, and XRPD analyses and the copper local environment was investigated using X-ray absorption spectroscopy. The analyses of high-resolution Cu-K edge XANES and EXAFS spectra suggest that, in red samples, copper is present as monovalent cations coordinated to the oxygen atoms of the glass framework, accompanied by metallic clusters. In green samples all the copper cations are incorporated in the glass matrix.

ARLETTI R.; QUARTIERI S.; VEZZALINI G. ( 2006 ) - Glass mosaic tesserae from Pompei: an archeometrical investigation (Bardi Editore:via Piave 7, I 00186 Rome Italy:011 39 06 4817656, 011 39 6 68801442, EMAIL: bardied@tin.it, INTERNET: http://space.tin.it/lettura/pabardi, Fax: 011 39 06 48912574 ) - PERIODICO DI MINERALOGIA - n. volume 75 - pp. da 25 a 38 ISSN: 0369-8963 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work reports the results of an archaeometrical investigation performed, through a multitechniqueapproach, on a series of Roman glass mosaic tesserae found in Pompeii excavations.Chemical and mineralogical analyses of mosaic tesserae of different colours were performed inorder to single out the colouring and opacifying agents employed in Roman times. Moreover, dueto the paucity of information on the production technology of mosaic tesserae, the chemical dataare compared with that of common transparent glass found at the same site, in order to evaluatewhether vessels and mosaic tiles could have been prepared with the same recipes and startingfrom the same glass batch. The chemical analyses were performed by Electron Microprobe,whereas the mineralogical investigation on the opaque samples were carried out by couplingScanning Electron Microscopy and X-ray Powder Diffraction. The results obtained show that allthe analysed samples have the typical composition of natron-based glass. The similarities with thechemical composition - at least in terms of major elements - of common translucent glass couldsuggest the use of the same raw materials for the preparation of the batch. All opaque blue andgreen tesserae contain crystalline aggregates respectively of calcium and lead antimonates, exceptone blue tessera, which contains traces of cuprorivaite and quartz (Egyptian blue pigment). Thered sample shows the presence of cuprite aggregates dispersed in a lead-rich matrix.This paper is dedicated to the memory of friend and colleague Filippo Olmi, who prematurelypassed away few months ago.

CARPENITO G.; LEVI S.T.; VEZZALINI G. ( 2006 ) - Indagini archeometriche della frazione fine di ceramiche “d’impasto” provenienti da siti Terramaricoli del territorio modenese ( AIAR 2006 - - 1-3 febbraio 2006) ( - IV Congresso Nazionale di Archeometria scienza e beni culturali, A.I.Ar. Pisa, 1-3 Febbraio 2006. ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R.; CIARALLO A.; QUARTIERI S.; SABATINO G.; VEZZALINI G. ( 2005 ) - Indagini archeometriche su vetri pompeiani: il caso delle pedine da gioco. ( - Scienze e archeologia. Le scienze ambientali-Le scienze Chimico Fisiche ) (Ciarallo A. e Baraldi P. POMPEI ITA ) - pp. da 49 a 54 ISBN: 978 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Tra i reperti vitrei rinvenuti negli scavi di Pompei si riconoscono piccoli oggetti di pasta vitrea classificati come pedine da gioco. Essi presentano un’ampia gamma di colorazioni e sono quindi di grande interesse per indagini di carattere archeometrico essenzialmente rivolte allo studio dei coloranti e degli opacizzanti utilizzati in epoca romana. A questo scopo sono state eseguite analisi morfologiche, chimiche e mineralogiche su 8 campioni opachi e 2 trasparenti. Le analisi chimiche sono state ottenute utilizzando microsonda elettronica, fluorescenza a raggi X e spettrometria EDS. Per identificare la natura delle fasi cristalline presenti all’interno delle paste vitree sono stati raccolti spettri di diffrazione a raggi X. I risultati ottenuti hanno permesso di individuare la presenza di agenti opacizzanti all’interno delle 8 pedine opache, quali antimoniati di calcio e piombo e particelle metalliche di rame. Al contrario, all’interno delle pedine trasparenti non sono state rinvenute particelle cristalline.

ARLETTI R.; GIORDANI N.; TARPINI R.; VEZZALINI G. ( 2005 ) - Archeometrical analysis of glass of western Emilia Romagna (Italy) from the imperial age. ( - Annales du 16e CONGRES de l’ASSOCIATION INTERNATIONALE pour l’HISTOIRE du VERRE, London 2003. ) (Arrowsmith BRISTOL GBR ) - n. volume - - pp. da 80 a 84 ISBN: 9789072290052 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Recent studies have allowed a typological and chronological characterization of Roman glass dated from the 1st to the 4th century AD. The samples have beenwere recovered from several archaeological sites during a surface survey on the plain South south of the river Po, which was a crucial transit area both via land and river. The chemical composition of 79 glass fragments of different typology was obtained by WDS-XRF and EMPA. The results were treated with hierarchical agglomerative cluster analysis. All the analysed samples resulted Silica-Soda-Lime glass. The differences in the chemical composition were mainly related to the colour and the age of the samples, whereas no relation was found with artefact typology or site of the find. The chemical composition of Padana plain glass was compared with literature data for samples of the same period coming from Aosta and Aquileia.

FOIS E.; GAMBA A.; TABACCHI G.; QUARTIERI S.; ARLETTI R.; VEZZALINI G. ( 2005 ) - High-pressure behaviour of yugawaralite at different water content: an ab initio study. ( - Oxide Based Materials. New sources, novel phases, new applications. Series: Studies in surface Science and catalysis. ) (Elsevier AMSTERDAM NLD ) - n. volume 155 - pp. da 271 a 280 ISBN: 9780444519757 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

The influence of the water content in a partially occupied water site in yugawaralite on the pressure-induced structural modifications of this zeolite has been studied by means of ab initio molecular dynamics simulations. The effect of the water site occupancy has been singled out by comparing results from simulations, performed with the cell parameters determined via XRPD at rP and 8.8 GPa, on two model systems whose cell stoichiometry differs only by the presence of a water molecule in such a site. Our results show that the global P-induced changes of the framework structure upon compression are mainly attributable to the template effect of Ca extra-framework cations, while the presence or absence of water in a partially occupied site affects the framework structure only at short range distances from the site. However, the overall water content plays a fundamental role in stabilizing/destabilizing the zeolite structure as a function of pressure.

SABATINO G.; ARLETTI R.; QUARTIERI S.; TIGANO G.; TRISCARI M.; VEZZALINI G.; GIACOBBE C. ( 2005 ) - LA –ICP-MS study of trace elements in Bizantine glass finds from Ganzirri (Messina, I) ( Geoitalia 2005, V Forum Italiano di Scienze della Terra, - - 21-23 September 2005) - EPITOME - n. volume 1 [Abstract in rivista (266) - Abstract in Rivista]
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ARLETTI R.; QUARTIERI S.; SABATINO G.; TRISCARI M.; VEZZALINI G. ( 2005 ) - Colouring and opacifying agents in Roman glass: a multi-technique analytical approach ( XX Congress of the International Union of Crystallography - - 23-31 August 2005) ( - XX Congress of the International Union of Crystallography Florence, 23-31 August 2005 ) (IUCr Firenze ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R.; DALCONI M.C.; QUARTIERI S.; TRISCARI M.; VEZZALINI G. ( 2005 ) - Copper bearing Roman Glass: XAFS investigations. ( RICH congress - - 12-13 dicembre 2005) ( - - ) (- Trieste ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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Arletti R.; Galli E.; Vezzalini G.; Wise W.S. ( 2005 ) - Mazzite-Na, a new zeolite from Boron, California: Its description and crystal structure - AMERICAN MINERALOGIST - n. volume 90 - pp. da 1186 a 1191 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Mazzite-Na, Na(8)Al(8)Si(28)O(72)center dot 30H(2)O, is a new zeolite mineral species occurring in basalt at the bottom of the open pit of the U.S. Borax mine at Boron, California. It crystallizes as white, very thin, flexible fibers up to 2 mm in length, and commonly fills small cavities as satiny mats. The luster is vitreous, and the streak is white. The fineness of the fibers precludes the determination of the hardness and the observation of any cleavage. The observed and calculated densities are 2.16 and 2.18 g/cm(3), respectively. The mineral is uniaxial positive with n(epsilon) = 1.472(3) and n(omega) = 1.471(3). Electron-microprobe analyses yielded (in wt%) SiO2 57.65, Al2O3 14.35, Fe2O3 0.65, MgO 0.22, CaO 0.18, BaO 0.14, Na2O 8.07, K2O 0.03, and H2O 18.70 (TG analysis), which gives the empirical cell contents (Na7.52K0.02Mg0.16Ca0.09Ba0.03)[Fe0.24Al8.13Si27.71O72]center dot 29.98H(2)O. Mazzite-Na is hexagonal, P6(3)/mmc, a = 18.2343(7), c = 7.6371(2) angstrom, Z = 1. The strongest seven measured X-ray lines [d in angstrom(I)(hkl)] are: 9.08(100)(110), 6.86(70)(101), 5.95(70)(210), 4.681(40)(211), 3.787(80)(002), 3.511(40)(112), and 3.150(70)(500). The framework consists of columns of gmelinite cages parallel to c, cross-linked to form two types of channels; one has an elliptical 8-ring cross section and the other has a circular 12-ring cross section. The extra-framework Na cations are located at three different sites. NaI is at the center of the 6-ring between adjacent gmelinite cages and is coordinated by six framework oxygen atoms and two H2O molecules. NaII lies on the centerline of the 8-ring channel and is coordinated by four framework oxygen atoms and two H2O molecules. NaIII occupies sites along the walls of the 12-ring channel and is coordinated with two framework oxygen atom and four H2O molecules. With the naming of this mineral for its Na dominant composition the original mineral is renamed mazzite-Mg, and the name mazzite is raised to series status.

FOIS E.; GAMBA A.; TABACCHI G.; ARLETTI R.; QUARTIERI S.; VEZZALINI G. ( 2005 ) - The “template” effect of the extra-framework content on zeolite compression: The case of yugawaralite. (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 90 - pp. da 28 a 35 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The microscopic behavior of the Ca-zeolite yugawaralite has been studied by ab initio moleculardynamics simulations adopting experimental cell parameters obtained at pressures up to ∼9 GPa.Pressure-induced volume contraction occurs via rotations of quasi-rigid TO4 tetrahedra that reducethe size of the channels in which the extra-framework species are located. Such rotations are governedby deformation of the coordination polyhedron of Ca, which is made up of water and framework Oatoms. Contraction of the Ca-H2O distances is favored at moderate pressure; at higher pressure theshortening of Ca-framework O atom distances becomes prevalent. The hydrogen bond network playsa fundamental role in the overall response to pressure. Our results indicate that the high-P-induceddeformation of the framework structure is strictly correlated to the extra-framework species that actas templates in the compression process.

CARDARELLI A.; CARPENITO G.; LUGLI S.; MARCHETTI DORI S.; LEVI S.T; VEZZALINI G. ( 2005 ) - The fine fraction of protohistoric pottery from Terramare of Modena area. ( EMAC ’05, 8th European Meeting on Ancient Ceramics, Lyon 2005 - - 26-29 October 2005) ( - Archaeometric and Archaeological Approaches to Ceramics ) (Archaeopress Publishers of British Archaeological Reports Oxford GBR ) - n. volume BAR International Series 1691 - pp. da 69 a 74 ISBN: 9781407301297 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Bronze Age Impasto pottery from Gorzano Terramarawas analysed to identify raw materials and manufacturingtechniques. Impasto ceramic paste is a heterogeneousmixture of fine sediments and tempers. Ceramics andsediments surrounding the site were characterised throughpetrographic analysis, chemical analysis of major, minorand trace elements and X-ray powder diffraction. Theresults show that the fine fraction of the pottery is lowin carbonates, while most sediments are calcareous andshow different clay mineral/carbonate ratios. Only threesediment samples of the Niviano unit are chemically andmineralogically similar to the fine fraction of the pottery.However the higher concentration of Al2O3 in the potterysuggests the use of a raw material richer in clay mineralsand hence the possibility that sediment from the Nivianounit were partially levigated before use.

FIORI C.; VANDINI M.; ARLETTI R.; VEZZALINI G. ( 2005 ) - Il vetro musivo dell XI secolo del monastero di Dafni (Atene, Grecia) ( XI giornate di Studio del comitato nazionale Italiano AIHV - - December, 16-18 2005.) ( - XI giornate di Studio del comitato nazionale Italiano AIHV, Bologna, (Italy) December, 16-18 2005. ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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ARLETTI R.; BIAGGIO SIMONA S.; CARDANI VERGANI R.; VEZZALINI G. ( 2005 ) - Ipotesi di una produzione primaria di vetro in epoca romana nelle terre dell’attuale Canton Ticino ( XI giornate di Studio del comitato nazionale Italiano AIHV - - December,16-18 2005) ( - XI giornate di Studio del comitato nazionale Italiano AIHV, Bologna,Italy December,16-18 2005 ) (- - ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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BETTI M.C.; MEDICI C.; FOIS E.; GAMBA A.; TABACCHI G.; QUARTIERI S.; VEZZALINI G.; ZANARDI S. ( 2005 ) - Zeolite Gismondine under pressure: synchrotron XRPD and computer simulations studies ( VII Convegno Nazionale Scienza e Tecnologia delle Zeoliti joint with 1st Czech-Italian workshop on C - - 26-30 giugno 2005) ( - VII Convegno Nazionale Scienza e Tecnologia delle Zeoliti joint with 1st Czech-Italian workshop on Catalysis and Zeolites. Camigliatello Silano (CS, Italy), 26-30 giugno 2005 ) (- - ITA ) - n. volume - - pp. da 155 a 156 ISBN: 978 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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BETTI M. C.; QUARTIERI S.; VEZZALINI G.; FOIS E.; GAMBA A.; MEDICI C.; TABACCHI G.; ZANARDI S. ( 2005 ) - Synchrotron XRPD and computer simulations studies of zeolite gismondine under pressure ( Geoitalia 2005, V Forum Italiano di Scienze della Terra, - - 21-23 September 2005) - EPITOME - n. volume 1 - pp. da 230 a 231 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
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BETTI M.C.; FOIS E.; GAMBA A.; MEDICI C.; QUARTIERI S.; TABACCHI G.; VEZZALINI G.; ZANARDI S. ( 2005 ) - Zeolites gismondine and Li-ABW under pressure: synchrotron XRPD and MD simulations ( XX Congress of the International Union of Crystallography - - 23 -31 August 2005) ( - - ) (- Firenze ITA ) - n. volume - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
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CARDARELLI A.; CARPENITO G.; LEVI S.T.; VEZZALINI G. ( 2005 ) - The fine fraction of protohistoric pottery from Gorzano (Modena): an experimental approach. ( Geoitalia 2005, V Forum Italiano di Scienze della Terra, - - 21-23 September 2005) - EPITOME - n. volume 1 [Abstract in rivista (266) - Abstract in Rivista]
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ARLETTI R.; MASTELLONI M.A.; QUARTIERI S.; SABATINO G. ; TRISCARI M. ; VEZZALINI G. ( 2005 ) - Arcaeometrical analyses of glass cake and mosaic tesserae from Sicily ( Geoitalia 2005, V Forum Italiano di Scienze della Terra, - - 21-23 September 2005) - EPITOME - n. volume 1 - pp. da 21 a 23 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
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FERRO O.; QUARTIERI S.; VEZZALINI G.; CERIANI C.; FOIS E.; GAMBA A.; CRUCIANI G. ( 2004 ) - Dehydration dynamics of bikitaite: I. In situ synchrotron X-ray powder diffraction study (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 89 - pp. da 94 a 101 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

High-temperature behavior and the process of thermal dehydration in the natural zeolite bikitaitehave been studied by ab initio molecular dynamics simulations, and favorably compared with the X-raypowder diffraction data presented in Part I of this work (Ferro et al. 2003). The microscopic dynamicalbehavior of the extraframework species (water molecules and Li cations) has been characterized as afunction of temperature. Two regimes have been detected, and the transition is characterized by thebreaking of the one-dimensional water chain typical of bikitaite at room temperature. The elementarysteps for the diffusion of water inside the bikitaite channels have been studied by means of a rareevents-sampling technique (Bluemoon Ensemble). The activation free-energy for a site-to-site waterjump has been calculated and a mechanism for the dehydration process is proposed.

CERIANI C.; FOIS E.; GAMBA A.; TABACCHI G.; FERRO O.; QUARTIERI S.; VEZZALINI G. ( 2004 ) - Dehydration dynamics of bikitaite: II Ab initio molecular dynamics study. (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 89 - pp. da 102 a 109 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

High-temperature behavior and the process of thermal dehydration in the natural zeolite bikitaitehave been studied by ab initio molecular dynamics simulations, and favorably compared with the X-raypowder diffraction data presented in Part I of this work (Ferro et al. 2003). The microscopic dynamicalbehavior of the extraframework species (water molecules and Li cations) has been characterized as afunction of temperature. Two regimes have been detected, and the transition is characterized by thebreaking of the one-dimensional water chain typical of bikitaite at room temperature. The elementarysteps for the diffusion of water inside the bikitaite channels have been studied by means of a rareevents-sampling technique (Bluemoon Ensemble). The activation free-energy for a site-to-site waterjump has been calculated and a mechanism for the dehydration process is proposed.

Reginelli M.; Settembre D.; Bertoni A.; Rovini A.; Vezzalini G.; Gualtieri A.; Carpenito G. ( 2004 ) - Ottimizzazione di impasti da monoporosa - CERAMICA INFORMAZIONE - n. volume 438 - pp. da 855 a 868 ISSN: 0009-0271 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In questo studio sono state analizzate le proprietà tecnologiche di impasti da gres smaltato con composizioni chìmiche molto diverse, indagando quanto il chimismo e la mineralogia possano influenzare il coefficiente di dilatazione del prodotto finito. Attraverso le analisi condotte è stato possibile ipotizzare un rapporto ottimale SiO2/Al2O3 e Na2O/K2O rispetto ai parametri più critici del processo produttivo: macinazione, smaltatura e cottura. Questi dati, rappresentano la prima fase di un progetto di ricerca più ampio, nel corso del quale si dovranno studiare gli effetti della macinazione, della natura e delia quantità della fase vetrosa, sul coefficiente di dilatazione, fornendo un contributo, al confronto in corso sul tema, sia alle aziende, che agli enti dì ricerca istituzionaii.

ARLETTI R.; CIARALLO A.; QUARTIERI S.; SABATINO G.; VEZZALINI G. ( 2004 ) - Indagini archeometriche su vetri pompeiani: il caso delle pedine da gioco ( - Vitrum. Il vetro fra arte e scienza nel mondo romano. ) (Giunti SpA Firenze, Milano FIRENZE ITA ) - n. volume - - pp. da 169 a 170 ISBN: 9788809036628 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
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ARLETTI R; FERRO O; QUARTIERI S; SANI A; TABACCHI G; VEZZALINI G ( 2003 ) - Structural deformation mechanisms of zeolites under pressure (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 88 - pp. da 1416 a 1422 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The HP behavior of the natural zeolite yugawaralite and of the synthetic zeolite Na-A was studiedby in situ synchrotron X-ray powder diffraction, using a non-penetrating P-transmitting medium. Theunit-cell parameters of yugawaralite were refined up to the pressure of 10 GPa, at which reductionswere found of about 7, 2.4, 7, 1.3, and 15% for a, b, c, b, and V, respectively. Contractions of 6.5 and18.4% were found for a and V, respectively, for zeolite Na-A in the range 10–4 to 6.8 GPa. Diffractionpatterns collected during decompression show that the effects induced by high pressure on both samplesare almost completely reversible. These results are compared with those obtained under similar experimentalconditions for other natural zeolites, with the aim of rationalizing the deformation mechanismsof these porous materials and comparing their flexibility under high-pressure and high-temperatureconditions.

O. Ferro; E. Galli; G. Papp; S. Quartieri; S. Szakall; G. Vezzalini ( 2003 ) - A new occurrence of katoite and re-examination of the hydrogrossular group - EUROPEAN JOURNAL OF MINERALOGY - n. volume 15 (2) - pp. da 419 a 426 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new occurrence of katoite (Ca2.95Fe0.03A12.03(SiO4)1.12(OH)7.51; a = 12.286) found near Dunabogdány (Hungary), along with its structural refinement is reported here. The crystal-chemical data, the physical properties, and the structure refinement of this new member of the Ca3Al2(SiO4)3-Ca3Al2(O4H4)3 series indicate the presence of about 37% grossular. The positional disorder of the oxygen atom, a peculiar feature of the hydrogarnet structure, is described here in terms of both anisotropy along the d-O vector, and presence of two distinct oxygen sites (unsplit- and split-O models, respectively). The hydrogen atom was localised for both models in the difference Fourier map. The structural features of the katoite from Dunabogdány are compared with those of other hydrogrossulars and with the two end-members "anhydrous" grossular, and Si-free katoite. The results of the unsplit-O model refinement confirm the increase of the tetrahedron volume with the substitution of Si by 4H+. The geometry of the coordination polyhedra in the two configurations resulting from the split-O model are also discussed. This second model better describes from the crystallochemical point of view the substitution of Si4+ with 4H+ in the tetrahedra. However, the tetrahedra of the two dimensions are randomly distributed in the unit cell and hence domains of the two end-member configurations are not expected in katoite structure. This conclusion is also strengthened by the TEM study of katoite from Dunabogdany.

A. Alberti; G. Cruciani; E. Galli; S. Merlino; R. Millini; S. Quartieri; G. Vezzalini; S. Zanardi ( 2002 ) - Crystal structure of tetragonal and monoclinic polytypes of tschernichite, the natural counterpart of synthetic zeolite beta - JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL - n. volume 106 - pp. da 10277 a 10284 ISSN: 1520-6106 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The tetragonal and monoclinic polytypes of tschernichite (the natural counterpart of zeolite beta) from Mt. Adamson (Antarctica) were isolated and studied by single-crystal X-ray diffraction using a diffractometer equipped with a CCD detector. Diffraction patterns were interpreted with the help of the OD theory, and synthetic precession images allowed us to overcome ambiguities regarding the symmetry assignment. The two crystalline phases isolated are characterized as two MDO polytypes, tetragonal and monoclinic with different crystal sizes (small and large crystals, respectively), morphologies (single tetragonal dipyramids and radiating hemispherical groups, respectively), and chemistries (high and low Si/Al ratio, respectively). Both refined structures showed regular T-O distances (in the range 1.56-1.68 Angstrom), and extraframework ions spreading over a large number of sites with low occupancy. Many independent sites were identified in both polytypes: in the monoclinic type three sites are occupied by Ca, whereas in the tetragonal three are occupied by Ca and one by Mg. The location and coordination of the site with the highest Ca occupancy in the monoclinic polytype were satisfactorily reproduced by potential energy calculations.

BALLONE P; QUARTIERI S; SANI A; VEZZALINI G ( 2002 ) - High-pressure deformation mechanism in scolecite: a combined computational-experimental study (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 87 - pp. da 1194 a 1206 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The pressure-induced structural modifications in scolecite were studied by means of in-situ synchrotron X-ray powder diffraction and by density functional computations. The experimental cell parameters were refined up to 7.5 GPa, pressure at which we found a reduction of 4.0, 5.0, 2.0, 0.9 and 11 %, in a, b, c,  and V, respectively. A slight anomaly in the slope of the volume vs pressure dependence was observed at about 6 GPa, suggesting an enhanced compressibility at higher pressures. The weakening and broadening of the diffraction peaks reveal the growth of a disordered phase with increasing pressure, preventing the refinement of the lattice parameters above 7.5 GPa. Diffraction patterns collected in decompression show that the disordering is irreversible. Atomic coordinates within unit cells of different dimensions were determined by means of Car-Parrinello simulations. The relatively discontinuous rise in compressibility at about 6 GPa is reproduced by the computation, that allows us to attribute it to the re-organization of the hydrogen bonding network, with the formation of water dimers. Moreover, we found that, with increasing pressure, the tetrahedral chains, parallel to c, rotate along their elongation axis and display an increasing twisting along an axis perpendicular to c. At the same time, we observed the progressive squashing of the channels. We discuss the modification of the Ca polyhedra under pressure, and the increase (from 4 to 5) of the coordination number of one of the two Al atoms, resulting from the approach of a water molecule. We speculate that this last transformation triggers the irreversible disordering of the system.

FERRO O; QUARTIERI S; VEZZALINI G; FOIS E; GAMBA A; TABACCHI G ( 2002 ) - High pressure behaviour of bikitaite: an integrated theoretical and experimental approach (Mineralogical Society of America:1015 18th Street Northwest, Suite 601:Washington, DC 20036:(202)775-4344, EMAIL: business@minsocam.org, INTERNET: http://www.minsocam.org, Fax: (202)775-0018 ) - AMERICAN MINERALOGIST - n. volume 87 - pp. da 1415 a 1425 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The pressure-induced structural modifications in the zeolite bikitaite are studied by means of in-situ synchrotron X-ray powder diffraction and ab initio molecular dynamics. The experimental cell parameters were refined up to 9 GPa, pressure at which we found a reduction of 4.5, 4.5, 6.3 and 15% in a, b, c, and V, respectively. Minor variations were observed for the cell angles. The complete X-ray amorphization is not achieved in the investigated P range, moreover the P-induced effects on bikitaite structure are completely reversible. Since it was possible to extract only the cell parameters from the powder patterns, atomic coordinates at 5.7 and 9.0 GPa were obtained by means of Car-Parrinello simulations using the unit cells parameters experimentally determined at these pressures. The analysis of the computational results at the increasing pressures evidenced that: the volume contraction is essentially due to the rotations of the tetrahedra; the 8-ring channels become more circular; the pyroxene chain becomes more corrugated in the bc plane; the mean Li-O bond distances and the coordination polyhedral volumes decrease with increasing pressure without significant distortion of the internal angles. The peculiar aspect of bikitaite structure, i.e. the presence in the channels of a "floating" one-dimensional water chain, is only partially maintained at high pressure: the compression brings framework oxygens close enough to water hydrogens to allow the formation of host-guest hydrogen bonds, without, however, destroying the one-dimensional chain.

FOIS E.; GAMBA A.; TABACCHI G.; FERRO O.; QUARTIERI S.; VEZZALINI G. ( 2002 ) - A theoretical investigation on pressure-induced changes in the vibrational spectrum of zeolite bikitaite ( - Impact of zeolites and other porous materials on the new technologies at the beginning of the new millennium ) (Elsevier AMSTERDAM NLD ) - n. volume 142 - pp. da 1877 a 1884 ISBN: 9780444511744 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
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FOIS E.; GAMBA A.; TABACCHI G.; QUARTIERI S.; M. VEZZALINI ( 2001 ) - Water molecules in single file: First -principles studies of one-dimensional water chains in zeolites. (American Chemical Society, Washington, D.C. ) - JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL - n. volume 105 - pp. da 3012 a 3016 ISSN: 1520-6106 [Articolo in rivista (262) - Articolo su rivista]
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A. ALBERTI; G. CRUCIANI; E. GALLI; S. MERLINO; R. MILLINI; S. QUARTIERI; G. VEZZALINI; S. ZANARDI ( 2001 ) - Pentasil zeolites from Antarctica: from mineralogy to zeolite science and technology ( - Studies in Surface Science and Catalysis ) (Elsevier AMSTERDAM NLD ) - n. volume 135 - pp. da 83 a 91 ISBN: 9780444502384 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

In the course of a systematic investigation of zeolites from Northern Victoria land, Antarctica, a large number of zeolitic species was identified in the jurassic Ferrar Dolerites of Mt. Adamson. Noteworthy was the presence of three new zeolites: gottardiite, the natural counterpart of the synthetic NU-87, terranovaite, and mutinaite, the analogue of ZSM-5, aswell as the two very rare zeolites tschernichite, the counterpart of zeolite beta, and boggsite.The chemical and crystallographic properties of these natural materials were compared with those of their synthetic analogues. The tetragonal and monoclinic polymorphic phases,intergrown in the beta zeolite, were isolated and structurally refined in tschernichite crystals, which differ by crystal size, morphology and chemistry. The occurrence of these naturalzeolites demonstrates that the chemical existence field of their synthetic counterparts is larger than that argued up to now, and that their synthesis can be obtained in the absence ofan organic template.

FOIS E; GAMBA A; TABACCHI G; QUARTIERI S; M. VEZZALINI ( 2001 ) - On the collective properties of water molecules in one-dimensional zeolitic channels (Royal Society of Chemistry:Thomas Graham House, Science Park, Cambridge CB4 0WF United Kingdom:011 44 1223 432360, EMAIL: sales@rsc.org, INTERNET: http://www.rsc.org, http://www.chensoc.org, Fax: 011 44 1223 423429 ) - PHYSICAL CHEMISTRY CHEMICAL PHYSICS - n. volume 3 - pp. da 4158 a 4163 ISSN: 1463-9076 [Articolo in rivista (262) - Articolo su rivista]
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ALBERTI A; M. VEZZALINI; QUARTIERI S; CRUCIANI G; BORDIGA S ( 2001 ) - Rehydration mechanisms in zeolites: reversibility of the TOT breaking and tetrahedral cation migration in brewsterite (Elsevier Science Incorporated / NY Journals:Madison Square Station, PO Box 882:New York, NY 10159:(212)633-3730, EMAIL: usinfo-f@elsevier.com, INTERNET: http://www.elsevier.com, Fax: (212)633-3680 ) - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 42 - pp. da 277 a 287 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
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VEZZALINI G.; QUARTIERI S; SANI A; LEVY D. ( 2001 ) - Structural modifications induced by high pressure in scolecite and heulandite: in-situ synchrotron X-ray Powder diffraction study ( - Zeolites and mesoporous materials at the dawn of the 21st century.Studies in surface science and catalysis. ) (Elsevier Amsterdam NLD ) - n. volume 135 - pp. da 09 a 17 ISBN: 9780444502384 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

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SACERDOTI M; M. VEZZALINI; QUARTIERI S ( 2000 ) - Dehydration mechanism in brewsterite: single-crystal X-ray diffraction study (Elsevier Science Incorporated / NY Journals:Madison Square Station, PO Box 882:New York, NY 10159:(212)633-3730, EMAIL: usinfo-f@elsevier.com, INTERNET: http://www.elsevier.com, Fax: (212)633-3680 ) - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 41 - pp. da 107 a 118 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
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SANI A.; VEZZALINI G.; CIAMBELLI P.; RAPACCIUOLO M.T. ( 1999 ) - Crystal structure of hydrated partially NH4-exchanged heulandite (Elsevier Science Incorporated / NY Journals:Madison Square Station, PO Box 882:New York, NY 10159:(212)633-3730, EMAIL: usinfo-f@elsevier.com, INTERNET: http://www.elsevier.com, Fax: (212)633-3680 ) - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 31 - pp. da 263 a 270 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
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SACERDOTI M; SANI A; M. VEZZALINI ( 1999 ) - Structural refinement of two barrerites form Alaska (Elsevier Science Incorporated / NY Journals:Madison Square Station, PO Box 882:New York, NY 10159:(212)633-3730, EMAIL: usinfo-f@elsevier.com, INTERNET: http://www.elsevier.com, Fax: (212)633-3680 ) - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 30 - pp. da 103 a 109 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
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ALBERTI A.; SACERDOTI M.; QUARTIERI S.; VEZZALINI G. ( 1999 ) - Heating-induced phase transformation in zeolite brewsterite: new 4- and 5-coordinated (Si, Al) sites. (Springer Verlag Germany:Tiergartenstrasse 17, D 69121 Heidelberg Germany:011 49 6221 3450, EMAIL: g.braun@springer.de, INTERNET: http://www.springer.de, Fax: 011 49 6221 345229 ) - PHYSICS AND CHEMISTRY OF MINERALS - n. volume 26 - pp. da 181 a 186 ISSN: 0342-1791 [Articolo in rivista (262) - Articolo su rivista]
Abstract

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S. Quartieri; A. Sani; G. Vezzalini; E. Galli; E. Fois; A. Gamba; G. Tabacchi ( 1999 ) - One-dimensional ice in bikitaite: single-crystal X-ray diffraction, infra-red spectroscopy and ab-initio molecular dynamics studies - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 30 - pp. da 77 a 87 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The crystal structure of bikitaite, Li-2[Al2Si4O12]. 2H(2)O, from North Carolina (USA) is triclinic, space group P1, with a=8.6146(6) Angstrom, b=4.9570(5) Angstrom, c=7.6032(6) Angstrom, alpha=89.899(8)degrees, beta=114.394(5)degrees, gamma=89.934(7)degrees. The structure was refined using 8225 reflections, in the angular range 5<2 theta<84 degrees, and yielded an R-W=3.02%. The average T-O distances and the 'average long-range order coefficient' S calculated for the framework tetrahedral sites indicates an almost complete (Si,Al) ordering, similar to that found for bikitaite from Bikita (Zimbabwe) [G. Bissert, F.N. Liebau, Jb. Miner. Mh. H 6 (1986) 241] and in contrast to the partially or completely disordered structures refined in the space groups P1 and P2(1) on samples from the same locality [K. Stahl, Angstrom. Kvick, S. Ghose, Zeolites 9 (1989) 303; V. Kocman, R. Gait, J. Rucklidge, Am. Mineral. 59 (1974) 71]. In parallel, a series of ab-initio molecular dynamics simulations was performed on systems with the stoichiometry and the cell parameters of bikitaite from North Carolina, but with various (Si, Al) distributions. The micro-IR spectrum of bikitaite is also reported and compared with the simulated vibrational bands. Both experimental and simulation results are consistent with the literature data and confirm the presence of a stable one-dimensional chain of hydrogen-bonded water molecules. The presence and the stability of this 'one-dimensional ice' is independent of the (Si, Al) distribution in the framework. (C) 1999 Elsevier Science B.V. All rights reserved.

FOIS E.; TABACCHI G.; QUARTIERI S.; VEZZALINI G. ( 1999 ) - Dipolar host/guest interactions and geometrical confinement at the basis of the stability of one dimensional ice in zeolite bikitaite (American Institute of Physics:2 Huntington Quadrangle, Suite 1NO1:Melville, NY 11747:(800)344-6902, (631)576-2287, EMAIL: subs@aip.org, INTERNET: http://www.aip.org, Fax: (516)349-9704 ) - THE JOURNAL OF CHEMICAL PHYSICS - n. volume 111 - pp. da 355 a 359 ISSN: 0021-9606 [Articolo in rivista (262) - Articolo su rivista]
Abstract

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G. VEZZALINI; ALBERTI A; SANI A; TRISCARI M ( 1999 ) - The dehydration process in amicite (Elsevier Science Incorporated / NY Journals:Madison Square Station, PO Box 882:New York, NY 10159:(212)633-3730, EMAIL: usinfo-f@elsevier.com, INTERNET: http://www.elsevier.com, Fax: (212)633-3680 ) - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 31 - pp. da 253 a 262 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

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ALBERTI A; MARTUCCI A; SACERDOTI M; QUARTIERI S; M. VEZZALINI; CIAMBELLI P; RAPACCIUOLO M ( 1999 ) - Crystal structure of hydrated partially and completely NH4-exchanged forms of stilbite ( - Proceedings of the 12th International Zeolite Conference. ) (MRS Publications WARRENDALE USA ) - n. volume IV - pp. da 2345 a 2354 ISBN: 978 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

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MARTUCCI A; ALBERTI A; SACERDOTI M; VEZZALINI G; CIAMBELLI P; RAPACCIUOLO M ( 1999 ) - Crystal structure refinement of NH4-exchanged barrerite ( - Zeolite '97 5th International Conference on the Occurrence, Properties and Utilization of Natural Zeolites, Ischia, September 21-29, 1997. ) (A. De Frede Napoli ITA ) - n. volume - - pp. da 45 a 51 ISBN: 978 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

A crystal-structure refinement of a hydrated NH4-exchanged barrerite was carrued out on single crystal X-ray diffraction data. The real simmetry Amma of natural barrerite became Fmmm.

P. Orlandi; M. Pasero; G. Vezzalini ( 1998 ) - Scandiobabingtonite, a new mineral from the Baveno pegmatite, Piedmont, Italy - AMERICAN MINERALOGIST - n. volume 83 - pp. da 1330 a 1334 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Scandiobabingtonite, ideally Ca2(Fe2+,Mn)ScSi5O14(OH) is the scandium analog of babingtonite; it was found in a pegmatitic cavity of the Baveno granite assocd. with orthoclase, albite, muscovite, stilbite, and fluorite. Its optics are biaxial (+) with 2V = 64(2)°, α = 1.686(2), β = 1.694(3), γ = 1.709(2). Dmeas = 3.24(5) g/cm3, Dcalc = 3.24 g/cm3, and Z = 2. Scandiobabingtonite is colorless or pale gray-green, transparent, with vitreous luster. It occurs as submillimeter sized, short, tabular crystals, slightly elongated on [001], and characterized by the assocn. of forms {010}, {001}, {110}, {1‾10}, and {101}. It occurs also as a thin rim encrusting small crystals of babingtonite. The strongest lines in the X-ray powder pattern are at 2.969 (S), 2.895 (S), 3.14 (mS), and 2.755 (mS) Å. The mineral is triclinic, space group P‾1, with a = 7.536(2), b = 11.734(2), c = 6.748(2) Å, α = 91.70(2), β - 93.86(2), γ = 104.53(2)°. Scandiobabingtonite is isostructural with babingtonite, with Sc replacing Fe3- in sixfold coordination, but no substitution of Fe2+ by Sc takes place. Due to the lack of a suitably large crystal of the new species, such a replacement has been confirmed by refining the crystal structure of a Sc-rich babingtonite (final R = 0.047) using single-crystal X-ray diffraction (XRD) data.

D. S. Coombs; A. Alberti; T. Armbruster; G. Artioli; C. Colella; E. Galli; J.D. Grice; F. Liebau; J.A. Mandarino; H. Minato; E.H. Nickel; E. Passaglia; D.R. Peacor; S. Quartieri; R. Rinaldi; M. Ross; R.A. Sheppard; E. Tillmanns; G. Vezzalini ( 1998 ) - Recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names - MINERALOGICAL MAGAZINE - n. volume 62 - pp. da 533 a 571 ISSN: 0026-461X [Articolo in rivista (262) - Articolo su rivista]
Abstract

A review with 295 refs. This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Assocn. Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral used for this review, interrupted tetrahedral framework structures are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Sep. species are recognized in topol. distinctive compositional series in which different extra-framework cations are the most abundant in at. proportions. To name these, the appropriate chem. symbol is attached by a hyphen to the series name as a suffix except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topol. distinctive framework do not in general provide adequate grounds for recognition of sep. species. Zeolite species are not to be distinguished solely on Si:Al ratio except for heulandite (Si:Al<4.0) and clinoptilolite (Si:Al≥4.0). Dehydration, partial hydration, and over-hydration are not sufficient grounds for the recognition of sep. species of zeolites. Use of the term 'ideal formula' should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba; chabazite-Ca,-Na, -K; clinoptilolite-K, -Na, -Ca; dachiardite-Ca, -Na; erionite-Na, -K, -Ca; faujasite-Na, -Ca, -Mg; ferrierite-Mg, -K, -Na; gmelinite-Na, -Ca, -K; heulandite-Ca, -Na, -K, -Sr; levyne-Ca, -Na; paulingite-K, -Ca; phillipsite-Na, -Ca, -K; stilbite-Ca, -Na. Key refs., type locality, origin of name, chem. data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

D. S. Coombs; A. Alberti; T. Armbruster; G. Artioli; C. Colella; E. Galli; J.D. Grice; F. Liebau; J.A. Mandarino; H. Minato; E.H. Nickel; E. Passaglia; D.R. Peacor; S. Quartieri; R. Rinaldi; M. Ross; R.A. Sheppard; E. Tillmanns; G. Vezzalini ( 1998 ) - Recommended nomenclature for zeolite minerals. Report of the subcommittee on zeolites of the International Mineralogical Association, commission on new minerals and mineral names - EUROPEAN JOURNAL OF MINERALOGY - n. volume 10 - pp. da 1037 a 1081 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A review with many refs. on recommendations on zeolite nomenclature approved by the International Mineralogical Assocn. Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral, structures contg. an interrupted framework of tetrahedra are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Sep. species are recognized in topol. distinctive compositional series in which different extra-framework cations are the most abundant in at. proportions. The appropriate chem. symbol is attached by a hyphen to the series name as a suffix, except for the names harmotome, pollucite, and wairakite in the phillipsite, and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topol. distinctive frame work do not in general provide adequate grounds for recognition of sep. species. Zeolite species are not to be distinguished solely on Si:Al ratio except for heulandite (Si:Al < 4.0) and clinoptilolite (Si:Al ≥ 4.0). Dehydration, partial hydration, and over-hydration are not sufficient grounds for the recognition of sep. species of zeolites. Use of the term "ideal formula" should be avoided in referring to a simplified or averaged formula of zeolite. Newly recognized species in compositional series are described. Key refs., type locality, origin of name, chem. data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and 3 of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

D. S. Coombs; A. Alberti; T. Armbruster; G. Artioli; C. Colella; E. Galli; J.D. Grice; F. Liebau; J.A. Mandarino; H. Minato; E.H. Nickel; E. Passaglia; D.R. Peacor; S. Quartieri; R. Rinaldi; M. Ross; R.A. Sheppard; E. Tillmanns; G. Vezzalini ( 1997 ) - Recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names - CANADIAN MINERALOGIST - n. volume 35 - pp. da 1571 a 1606 ISSN: 0008-4476 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Assocn., Commission on New Minerals and Mineral Names (IMA,CNMMN). In a working definition of a zeolite mineral used in this paper, structures contg. an interrupted framework of tetrahedra are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Sep. species are recognized in topol. distinctive compositional series in which different extra-framework cations are the most abundant in at. proportions. To name these, the appropriate chem. symbol is attached by a hyphen to the series name as a suffix, except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topol. distinctive framework do not in general provide adequate grounds for recognition of sep. species. Zeolite species are not to be distinguished solely on the ratio Si: Al except for heulandite (Si: Al < 4.0) and clinoptilolite (Si: Al ≥ 4.0). Dehydration, partial hydration, and overhydration are not sufficient grounds for the recognition of sep. species of zeolites. Use of the term "ideal formula" should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba, chabazite-Ca, -Na, -K, clinoptilolite-K, -Na, -Ca, dachiardite-Ca, -Na, erionite-Na, -K, -Ca, faujasite-Na, -Ca, -Mg, ferrierite-Mg, -K, -Na, gmelinite-Na, -Ca, -K, heulandite-Ca, -Na, -K, -Sr, levyne-Ca, -Na, paulingite-K, -Ca, phillipsite-Na, -Ca, -K, and stilbite-Ca, -Na. Key refs., type locality, origin of name, chem. data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

G. Vezzalini; S. Quartieri; E. Galli; A. Alberti; G. Cruciani; A. Kvick ( 1997 ) - Crystal structure of the zeolite mutinaite, the natural analog of ZSM-5 - ZEOLITES - n. volume 19 - pp. da 323 a 325 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

We describe the crystal structure of the high-silica zeolite mutinaite, recently found at Mt. Adamson (Northern Victoria Land, Antarctica). Mutinaite is the natural counterpart of the synthetic zeolite ZSM-5. The new mineral, (Na2.76K0.11Mg0.21Ca3.78) (Al11.20 Si84.91) · 60 H2O H2O, is orthorhombic, space group Pnma, with a = 20.201(2), b = 19.991(2), and c = 13.469(2) Å. A single-crystal X-ray diffraction expt. was performed at the synchrotron radiation source ESRF (Grenoble). No Si-Al order in the framework has been detected. Large distances between ions in the channels and framework oxygens suggest weak interactions between the framework and extraframework species.

E. Galli; G. Vezzalini; S. Quartieri; A. Alberti; M. Franzini ( 1997 ) - Mutinaite, a new zeolite from Antarctica: the natural counterpart of ZSM-5 - ZEOLITES - n. volume 19 - pp. da 318 a 322 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Mutinaite is the third new zeolite from Ferrar dolerites at Mt. Adamson (Northern Victoria Land, Antarctica). The mineral occurs as subspherical aggregates of tiny radiating lath-like fibers or as aggregates of transparent, colorless to pale-milky, tiny tabular crystals; it has vitreous luster, white streak and good {100} cleavage. Mutinaite is brittle with measured and calcd. d. 2.14(3) and 2.17 g/cm3, resp. Optically, it is biaxial neg. with ns α = 1.485(2), β = 1.487(2) and γ = 1.488(2). The orientation is X = b, Y = a, Z = c. Mutinaite is orthorhombic with a = 20.223(7), b = 20.052(8), c = 13.491(5)Å, space group Pnma. The strongest powder X-ray diffraction lines are (d(Å), l, hkl): 11.20, 84, 101, 011; 9.98, 35, 200,020; 3.85, 100, 501, 051; 3.75, 98, 303; 3.67, 27, 133; 3.00, 32, 503. The framework topol. is that of the synthetic zeolite ZSM-5. The chem. formula is: (Na2.76K0.11Mg0.21Ca3.78)Σ=6.86(Al11.20Si84.91)Σ=96.11O192·60H2O. The Si/Al ratio, equal to 7.6, is the highest found in a natural zeolite. Thermal stability and rehydration capacity are very high.

A. Alberti; A. Martucci; E. Galli; G. Vezzalini ( 1997 ) - A reexamination of the crystal structure of erionite - ZEOLITES - n. volume 19 - pp. da 349 a 352 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The crystal structure of a natural erionite from Nizhnyaya Tunguska, Siberia (schematic formula K2Ca3.5Al9Si27O72·32H2O) has been refined to a residual wR of 0.044. The erionite framework can be described by a sequence AABAAC... of 6-membered rings of tetrahedra. The (Si, Al) distribution (24% of Al in T1 and 31% of Al in T2) is consistent with the strong disorder found in tetrahedral sites for all zeolites that can be described by a sequence of 6-rings. Erionite, as in the closely related zeolite offretite, shows a slight enrichment of Al in the single 6-ring. Potassium is at the center of the cancrinite cage and coordinates 6 framework oxygen atoms. Calcium atoms alternately occupy three sites, quite near each other, on the triad axis parallel to c, at the center of the erionite cage. Their coordination no. varies between 6 and 9. The marked differences in T-O distances found between hydrated and dehydrated erionite are explained in terms of interactions between extra-framework ions and framework oxygens.

G. Vezzalini; S. Quartieri; E. Galli ( 1997 ) - Occurrence and crystal structure of a Ca-pure willhendersonite - ZEOLITES - n. volume 19 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The paper reports the occurrence and the crystal-chem. data of willhendersonite from the breccia ridge of a melilitite plug at Colle Fabbri, Terni, Italy. The chem. data suggests extensive chem. variability, ranging from the compn. of the holotype sample (CaKAl3Si3O12: 5 H2O) through intermediate compns., to a Ca-pure term; thus it becomes necessary for a chem. redefinition of the zeolite. The structural refinement of a Ca-pure willhendersonite single crystal exhibits the same space group and Si/Al ordering as the holotype willhendersonite, but it displays significant differences in the distribution of the extra-framework species. These structural features are discussed in the light of a comparison with the structures of the holotype willhendersonite and natural and exchanged chabazites.

E. Galli; S. Quartieri; G. Vezzalini; A. Alberti; M. Franzini ( 1997 ) - Terranovaite from Antarctica: a new 'pentasil' zeolite - AMERICAN MINERALOGIST - n. volume 82 - pp. da 423 a 429 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new high-silica zeolite, terranovaite, was recently found in cavities of Ferrar dolerites at Mt. Adamson (northern Victoria Land, Antarctica). The mineral [(Na4.2K0.2Mg0.2Ca3.7)8.3(Al12.3Si67.7)80.0O160·>29 H2O] occurs as globular masses that flake off in transparent lamellae. It has a vitreous luster, white streak, {010} perfect cleavage, and {001} distinct parting. The obsd. d. is 2.13 ± 0.02 g/cm3. Optically, it is biaxial pos., with 2V = 65°, α = 1.476, β = 1.478, γ = 1.483 (all ± 0.002). The orientation is X = c, Y = a, and Z = b. Terranovaite is orthorhombic with a = 9.747(1), b = 23.880(2), c = 20.068(2) Å and topol. symmetry Cmcm. The strongest powder x-ray diffraction lines are [d(Å), I, hkl]: 11.94,40,020; 10.16,65,021,002; 9.04,33,110; 3.79,100,025,240; 3.61,40,153. Terranovaite topol., hitherto unknown in either natural or synthetic zeolites, is characterized by the presence of pentasil chains and of a two-dimensional ten-membered ring channel system. The mineral was named terranovaite after the Italian Antarctic Station at Terranova Bay, Antarctica.

E. Galli; S. Quartieri; G. Vezzalini; A. Alberti ( 1996 ) - Gottardiite, a new high-silica zeolite from Antarctica: the natural counterpart of synthetic NU-87 - EUROPEAN JOURNAL OF MINERALOGY - n. volume 8 - pp. da 687 a 693 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Gottardiite was discovered in the Jurassic Ferrar dolerites of Mt. Adamson (Northern Victoria Land, Antarctica). The new zeolite occurs as subparallel aggregates of transparent pseudo-hexagonal lamellae. The mineral is orthorhombic, space group Cmca, with a=13.698(2), b=25.213(3), and c=22.660(2) Å. The strongest x-ray diffraction lines are (in Å): 11.34(100), 4.37(79), 4.01(57), 3.282(68). The Gottardiite framework topol. is the same as that of synthetic NU-87. The chem. formula is: Na2.5K0.2Mg3.1Ca4.8Al18.8Si117.2O272.93H2O. The Si/Al ratio is 6.2, the highest found up to now in a natural zeolite. Gottardiite is optically biaxial (-), with α=1.480(2), β=1.485(2), γ=1.486(2), 2V<60°, where X=b, Y=a and Z=c. The d. is 2.14(4) g/cm3 (obs.), and 2.16 g/cm3 (calc.). Both thermal stability and rehydration capacity are very high. The name is in honor of Glauco Gottardi (1928-1988).

A. Alberti; G. Vezzalini; E. Galli; S. Quartieri ( 1996 ) - The crystal structure of gottardiite, a new natural zeolite - EUROPEAN JOURNAL OF MINERALOGY - n. volume 8 - pp. da 69 a 75 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Gottardiite is a new high-silica zeolite found in the Jurassic dolerites of Mt. Adamson (Victoria Land, Antarctica). Its unit-cell content is: Na2.5K0.2Mg3.1Ca4.9Al18.8Si117.2O272·93 H2O. The mineral is orthorhombic with a = 13.698(2), b = 25.213(3), c = 22.660(2) Å, topol. symmetry Fmmm and real symmetry Cmca. In the Fmmm symmetry there are oxygens on centers of symmetry, which cause energetically unfavorable T-O-T angles of 180°; in the Cmca symmetry the sets of ‾1, on which these oxygens lie, disappear. The topol. of gottardiite, which has not been found in other natural zeolites, is the same as that of synthetic zeolite NU-87; the latter, however, is characterized by a monoclinic symmetry P21/c (a = 14.32, b = 22.38, c = 25.09 Å, β = 151.5°). The framework of gottardiite can be described by the polyhedral units 5462 and 54. These units developing along [010] give rise to chains which, sharing edges with other analogous chains, form impermeable sheets parallel to (001). Each sheet is bonded to other analogous sheets through 4-rings of tetrahedra between, and parallel to the sheets. A 2-dimensional channel system parallel to (001) is present in gottardiite. Straight 10-ring channels run parallel to [100], whereas 12-ring channels "snake" in the [010] direction. Ten-ring and 12-ring channels are connected through 10-ring windows. The ion sites localized in the channels all have weak electron d. and large distances (>2.7 Å) from framework oxygens. An enrichment in Al in the tetrahedra of 4-rings can be envisaged.

Alberti A; Cruciani G; Galli E; Vezzalini G ( 1996 ) - A reexamination of the crystal structure of the zeolite offretite - ZEOLITES - n. volume 17 - pp. da 457 a 461 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The crystal structure of a natural offretite from Poia Creek, Adamello, Italy (schematic formula KCaMgAl5Si13O36:17H(2)O) has been refined to a residual wR of 0.038. The offretite framework can be described by a sequence AABAAB ... of 6-membered rings of tetrahedra. The (SI,AI) distribution (29% of Al in T1 and 37% of Al in T2) is consistent with the disorder found in tetrahedral sites for all zeolites describable by sequences of 6-rings. K is at the center of the cancrinite cage and is coordinated to 6 framework oxygen atoms. Mg, placed at the center of the gmelinite cage, is coordinated to 6 water molecules; 4 of these are disordered on 9 possible positions relative to two sites with multiplicity 6 and 3, respectively. Ca atoms alternately occupy two sites near each other, at the center of the wide channel parallel to parameter c, and are octahedrally coordinated to the same water molecules. The strong differences in the T-O distances found between hydrated and dehydrated offretite are here explained in terms of interactions between extraframework ions and framework oxygens.

A. Alberti; S. Quartieri; G. Vezzalini ( 1996 ) - Thermal behavior of zeolites. Single crystal x-ray study of dehydration and rehydration mechanism in yugawaralite - EUROPEAN JOURNAL OF MINERALOGY - n. volume 8 - pp. da 1273 a 1282 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Dehydration and rehydration processes and phase transformations of yugawaralite (I) were studied by single crystal x-ray diffraction. I kept in vacuum at room temp. does not undergo any noticeable structural modifications. When I is heated at 100° in vacuum for 24 h, only the water mol. not coordinated with the Ca atom is lost (≈ 6%), while the 2 water mols. occupying alternative positions in the hydrated sample move into only one fully occupied site placed in an intermediate position: the Ca coordination remains virtually unchanged. At 150° a water loss of 53% is indicated, and the residual water mols. are localized in only 2 fully occupied sites. The Ca atoms are 6-coordinated by 4 framework O and the 2 residual water mols. The most relevant modifications of the framework are the increased difference between the Al-OCa-bonded and AI-OCa-nonbonded distances, and a lengthening (by ≈ 0.04 Å) and a narrowing (by ≈ 0.04 Å) of the structural units of I formed by a pair of 5-membered rings sharing an edge when compared with hydrated samples. At 180°, a sudden decrease of the I unit cell vol. occurs (≈ 12%), the cell parameter a is doubled, and the space group changes from Pc to Pn. The structure refinement of a crystal heated at 200° shows a further 50% loss of the residual water present at 150°, a collapsing of the channel system, and strong squashing of the framework. Owing to the doubling of parameter a there are 2 sym. independent Ca sites, both 6-coordinated with five framework O and 1 water mol. At 250°, I does not cause any significant modifications with respect to the structure at 200°. When I heated at 150° is brought back to room conditions for 2 wk, complete rehydration occurs; the water mols. are in the same positions and have the same occupancies as in the hydrated sample.

E. Galli; S. Quartieri; G. Vezzalini; A. Alberti ( 1995 ) - Boggsite and tschernichite-type zeolites from Mt. Adamson, Northern Victoria Land (Antarctica) - EUROPEAN JOURNAL OF MINERALOGY - n. volume 7 - pp. da 1029 a 1032 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Two very rare zeolites, boggsite and a tschernichite-type mineral, have been found in the basalts of Mt. Adamson, Terra Victoria Land, Antarctica. Boggsite from Antarctica is chem. characterized by a high Na content in comparison with that of the type locality of Goble, Oregon. Tschernichite-type zeolite is, both morphol. and chem., quite similar to tschernichite from Goble, but differences in X-ray powder diffraction patterns suggest that the minerals from the two localities have structures which can be described with different polytypic sequences.

G. Vezzalini; S. Quartieri; A. Rossi; A. Alberti ( 1994 ) - Occurrence of zeolites from Terra Victoria Land (Antarctica) - TERRA ANTARTICA - n. volume 1 - pp. da 96 a 99 ISSN: 1122-8628 [Articolo in rivista (262) - Articolo su rivista]
Abstract

We report the first study on zeolite minerals occuring in rocks from the Antarctic continent. the following zeolites were identified: heulandite, mordenite, erionite, levyne, chabazite, thomsonite, scolecite, epistilbiite. The microprobe analyses show that most Antarctica zeolites are richer in Si and monovalent cations with respect to the hydrothermal zeolites reported in literature. The chemical analysis and the X-ray diffraction pattern of an unidentified phase from Mt. Adamson with zeolitic characteristics are also reported.

E. Bonaccorsi; S. Merlino; P. Orlandi; M. Pasero; G. Vezzalini ( 1994 ) - Quadridavyne, [(Na,K)6Cl2][Ca2Cl2][Si6Al6O24], a new feldspathoid mineral from Vesuvius area - EUROPEAN JOURNAL OF MINERALOGY - n. volume 6 - pp. da 481 a 487 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new feldspathoid mineral, quadridavyne, belonging to the davyne group, is described. It was found in the locality Ottaviano, near Napoli, southern Italy, within products of the 1906 volcanic activity of Vesuvius. It occurs as transparent, colorless, prismatic crystals, elongated [001] with hexagonal outline. Twinning (1‾100) is frequent. The mineral is brittle, with hardness ca. 5, dmeas = 2.335(5), dcalc = 2.354 g/cm3. Optically it is uniaxial (+), with ω = 1.529(1) and ε = 1.532(1). Its ideal chem. formula, derived from electron microprobe data, is [(Na,K)6Cl2][Ca2Cl2][(Si6Al6O24)]. Quadridavyne is hexagonal, space group P63/m, a = 25.771(6), c = 5.371(1) Å, Z = 4. The structure of quadridavyne is topol. identical to that of davyne. The major difference lies in the long-range ordering of alk. cations (Na+ and K+) and chlorine within the open channels running along [001], resulting in the doubling of the a parameter.

A. Alberti; S. Quartieri; G. Vezzalini ( 1994 ) - Structural modifications induced by dehydration in yugawaralite ( - Zeolites and Related Microporous Materials ) (Elsevier Amsterdam NLD ) - n. volume 84 Part A - pp. da 637 a 644 ISBN: 0444818472 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

The dehydration behavior of yugawaralite has been studied by single crystal x-ray diffraction on three samples dehydrated under vacuum at 20, 150 and 200°C, resp. Yugawaralite held in vacuum at room temp. (r.T) - even for relatively long times - does not show noticeable structural changes with respect to untreated samples. The Ca atom remains coordinated to four framework oxygen atoms and to four water oxygens; two of these water mols. are disordered with two alternative oxygen positions. Yugawaralite heated at 150°C is characterized by a water loss as high as 54%, with all the residual water mols. in two fully occupied sites. The Ca atoms are 6-coordinated by four framework oxygens and the two residual water mols. The framework undergoes only minor modifications. The crystal heated at 200°C shows a further 50% loss of the residual water present at 150°C and a collapsing of the channel system: a sudden decrease of unit cell vol. occurs (about 13%), the cell parameter a is doubled, the space group changes from Pc to Pn, and the structure is strongly squashed. Owing to the doubling of parameter a, there are two sym. independent Ca sites; both are 6-coordinated, but now with five framework oxygens and one water mol.

A. Alberti; C. Colella; G. Oggiano; M. Pansini; G. Vezzalini ( 1994 ) - Zeolite production from waste kaolin-containing materials - MATERIALS ENGINEERING - n. volume 5 - pp. da 145 a 158 ISSN: 1120-7302 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Conversion of the kaolin-rich fraction of Florinas (Sardinia) sand into zeolite was studied. After a preliminary study on the original waste material to obtain, through a suitable sieving, a further increase of the kaolinite content and, through chem. and/or thermal treatments, an improvement of its reactivity, an exploratory systematic investigation on the hydrothermal transformation of the obtained products as a function of nature and concn. of the alk. contact soln., solid-to-liq. ratio, temp., and reaction time was carried out. The obtained products, characterized by x-ray, chem., and microscope analyses, were (a) zeolites A, P, and X, besides sodalite, in a sodium environment and (b) zeolite F and chabazite in a potassium environment. Further research was focused on the synthesis of zeolite A, presenting the advantage of good transformation yields and notable chances of application, demonstrating that it is possible to perform a near-quant. conversion of the reactive starting material into zeolite A, provided the raw material is previously purified from the quartz, feldspar, and muscovite impurities

R. Cabella; G. Lucchetti; A. Palenzona; S. Quartieri; G. Vezzalini ( 1993 ) - First occurrence of a barium-dominant brewsterite: Structural features - EUROPEAN JOURNAL OF MINERALOGY - n. volume 5 - pp. da 353 a 360 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

At the Cerchiara mine (La Spezia, Liguria, Italy), Ba-dominant brewsterite (BB) occurs as prismatic crystals filling veins in metacherts from the northern Apennine ophiolitic sequences. Electron microprobe anal. of BB suggested ((Ba1.80Sr0.02Na0.07Ca0.03K0.04) (Al4.29Si11.78)O32.nH2O); the dominant presence of Ba among the exchangeable cations is obsd.. The unit-cell parameters of BB are: a 6.790(1), b 17.581(4), and c 7.735(1) Å, β = 94.50(3)°. BB is optically biaxial (+), with ns α 1.514(2), β 1.516(2), and γ 1.528(2). Single-crystal refinement confirms the main features of the BB structure, apart from the extra-framework cations which spread over 3 sites, two of which with low occupancy. This occurrence of BB furnishes new information on the crystal chem. of this zeolite, up to now reported only as a Sr-dominant zeolite.

G. Vezzalini; S. Quartieri; A. Alberti ( 1993 ) - Structural modifications induced by dehydration in the zeolite gismondine - ZEOLITES - n. volume 13 - pp. da 34 a 42 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Gismondine from Ontalto di Castro, Italy [Ca3.91Al7.77Si8.22O32.17.57 H2O] with a 10.0199(4), b 10.6773(5), c 9.8316(1) Å, β 92.561(6)°, space group P21/c, dehydrated in vacuum for 1 and 24 h transformed into 2 phases, here called gismondine (1 h) and gismondine (24 h), resp. Gismondine (1 h) is characterized by 9.5% H2O loss and by a small decrease in the cell vol. (ΔV = 0.6%) with a 9.989(3), b 10.616(3), c 9.820(3) Å, and β 92.57(2)°, Rw = 7.6%. The framework is almost undistorted, but a rearrangement of H2O mols. causes a change in space group to P21, with formation of a more regular 6-coordinated Ca polyhedron. Gismondine (24 h) is characterized by the orthorhombic space group P212121 and a unit cell doubled with respect to the nondehydrated sample; a 13.902(9), b 8.892(4), and c 13.952(5) Å, Rw = 7.6%. More than 50% of H2O is lost, the framework is highly distorted, and the channels are strongly squashed. Residual H2O sites are fully occupied. Ca polyhedra are 7-fold coordinated and are linked by vertexes to form infinite chains.

C. Sabelli; P. Orlandi; G. Vezzalini ( 1992 ) - Coquandite, Sb6O8(SO4).H2O, a new mineral from Pereta, Tuscany, Italy, and two other localities - MINERALOGICAL MAGAZINE - n. volume 56 - pp. da 599 a 693 ISSN: 0026-461X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Coquandite, a new antimony oxy-sulfate hydrate, occurs as spheroidal knobs of silky fibers or, rarely, as tiny transparent colorless lamellar crystals on stibnite at the Pereta mine, Tuscany, Italy; it is assocd. with klebelsbergite, peretaite, valentinite, sulfur, gypsum, stibiconite, and senarmontite. Coquandite is triclinic P‾1, with a 11.434(7), b 29.77(4), c 11.314(4) Å, α 91.07(7)°, β 119.24(3)°, γ 92.82(1)°. It has a cell vol. of 3352(5) Å3 with Z = 12 and a calcd. d. of 5.78 g cm-3. The crystals, elongated along [001] and flattened on {010}, display polysynthetic twinning with (010) as the twin plane. Optically, they are biaxial (+) with z ≈ c, 2V » 60°, n = 2.08(5). The strongest lines of the x-ray powder pattern are [d in Å, (I), (hkl)] 14.84(50)(020), 9.27(41)(111, 110) 6.81(67)(130), 3.304(93)(090), 3.092(100)(330). Coquandite has also been found at the Cetine mine, Tuscany, Italy, and at the Lucky Knock mine, Tonasket, Okanogan County, Washington, USA. Microprobe chem. analyses (elemental microanal. for H) gave Sb2O3 88.91, SO3 8.35, CaO 0.04, Na2O 0.03, H2O 1.43, total 98.76 wt.%, corresponding to the empirical formula (Sb + S = 7) Sb5.98Ca0.01Na0.01O7.96(SO4)1.02.0.78H2O, and to the idealized formula Sb6O8(SO4).H2O. The IR spectrum, which confirms the presence of water in the formula, is given. A partial structural arrangement is also given: the Sb polyhedra lie in nine layers perpendicular to [010] and form 'hexagonally' shaped groups surrounded by SO4 tetrahedra.

G. Vezzalini; G. Artioli; S. Quartieri; H. Foy ( 1992 ) - The crystal chemistry of cowlesite - MINERALOGICAL MAGAZINE - n. volume 56 - pp. da 599 a 693 ISSN: 0026-461X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Cowlesite specimens from nine new occurrences in Northern Ireland and from eight localities previously reported in the literature, were crystal-chem. characterized. The chem. data for a total of 25 samples indicate a compn. close to the stoichiometric formula for cowlesite and a very limited compositional range. X-ray powder diffraction spectra were performed on 8 samples. The crystallog. unit cell permits proper indexing of the x-ray powder diffraction patterns as orthorhombic, with unit cell consts. close to a 23.3, b 30.6, c 25.0 Å and doubled with respect to those originally reported in the literature. The powder pattern and the TG curve are reported for an unidentified mineral species assocd. with cowlesite in one of the samples from Northern Ireland.

G. Vezzalini; S. Quartieri; E. Passaglia ( 1990 ) - Crystal structure of a potassium-rich natural gmelinite and comparison with the other refined gmelinite samples - NEUES JAHRBUCH FUR MINERALOGIE MONATSHEFTE - n. volume 11 - pp. da 504 a 516 ISSN: 0028-3649 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A complete crystallochem. characterization of a gmelinite sample from Fara Vicentina (Vicenza, Italy) is given. The mineral is anomalous for the prevalence of K (2.72 atoms per unit cell) among the exchangeable cations. The lattice consts. are a = 13.621(3) and c = 10.254(1) Å. Its crystal structure was refined down to Rw = 5.92% and compared with the structures reported for Na-, Ca- and K-rich gmelinites in the literature; the sample studied is characterized by a very low occupancy (3%) of 1 (C2) of the 2 exchangeable cation sites and by water mols. distributed among 8 partially occupied sites. A correlation involving the C2 site and the geometry of the tetrahedral framework was found between the bond strengths: with decrease in the bond strength, the shape of the 8-ring of the gmelinite cage becomes more circular, the double 6-ring becomes more hexagonal and, consequently, the c parameter increases and the a parameter decreases. Post-crystn. cation exchanges explain the present chem. compn. of the mineral.

E. Passaglia; G. Vezzalini; R. Carnevali ( 1990 ) - Diagenetic chabazites and phillipsites in Italy: Crystal chemistry and genesis - EUROPEAN JOURNAL OF MINERALOGY - n. volume 2 - pp. da 827 a 839 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Diagenetic phillipsites and chabazites are the main constituents of many Italian zeolitized volcaniclastic deposits, and represent great economic value. The samples show chem. peculiarities which are closely correlated with the chem. of their parent glasses and diagenetic environments of crystn. The obsd. chem. trends reflect the following zeolitization processes: (1) samples crystallize in "hydrol. open systems" or "geoautoclaves" from alkali-potassic glasses of intermediate acidity (phonolitic, trachytic compns.) or low acidity (tephritic compns.) are peculiarly high in K and display low Si/Al ratios; (2) the low Si/Al ratios and high Na contents of samples from the Vivara hyaloclastites agree with the trachybasaltic compn. of the parent glass and a diagenetic marine environment; and (3) the low Na and high Ca contents of both chabazite and phillipsite from Iblean hyaloclastites are explained by cation exchanges following their crystn. in a marine environment.

P. Orlandi; M. Pasero; G. Vezzalini ( 1990 ) - Calcio-ancylite-(Nd), a new REE-carbonate from Baveno, Italy - EUROPEAN JOURNAL OF MINERALOGY - n. volume 2 - pp. da 413 a 418 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Calcio-ancylite-(Nd), a new basic hydrated carbonate of calcium and rare earth elements (REE), occurs as pink pine-cone-like crystals in miarolitic cavitieis of Baveno granite, Italy. Electron microprobe anal. yields the formula: (Nd0.90Ce0.64Sm0.33Gd0.28Y0.26Pr0.15Dy00.07Tm0.03)2.80Ca1.20(CO3)3.98(OH) ∞2∞.∞8∞41.01H2O (Z = 1). The mineral is monoclinic; Pm11, with a = 4.976(2), b = 8.468(2), c = 7.212(2) Å, α = 90.04(3)°; measured d. > 4.02 and diffraction pattern are [d (Å), (hkl), I]: 4.26 (100), 100; 2.905, (102), 90; 2.048; (221), 80. The crystal structure refinement (Rw = 0.036) confirms the main features of ancylite-(Ce), but provides evidence for a different distribution of alk. earth and REE in the M sites. A reexamn. of the discredited mineral weibycite from Baveno shows that it is a calcio-ancylite-(Ce) with variable REE content.

S. Quartieri; G. Vezzalini; A. Alberti ( 1990 ) - Dachiardite from Hokiya-Dake: Evidence of a new topology - EUROPEAN JOURNAL OF MINERALOGY - n. volume 2 - pp. da 187 a 193 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A refinement of the crystal structure of dachiardite from Hokiya-dak, Japan, shows the presence (16% modal abundance) of domains of the hypothetical structure called "modified" dachiardite by S. Merlino (1975, 1976) assocd. with domains of "normal" dachiardite. As in the Elba dachiardite, 2 acentric framework configurations are present with the same frequency in the Hokiya-dake dachiardite, so that the statistical symmetry C2/m is maintained. This feature is interpreted as a tendency (common to all zeolites) to avoid T-O-T angles of 180° in the topol. C2/m symmetry of dachiardite. As with the related structures of mordenite and epistilbite, a remarkable Al-enrichment is found in the tetrahydrons of the 4-membered ring.

Y. Di Cossato Marzoni Fecia; P. Orlandi; G. Vezzalini ( 1989 ) - Rittmannite, a new mineral species of the whiteite group from the Mangualde granitic pegmatite, Portugal - CANADIAN MINERALOGIST - n. volume 27 - pp. da 447 a 449 ISSN: 0008-4476 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Rittmannite, a new mineral species, is the MnMnFe analog of whitelite. It was found in altered phosphatic "modules" from the Mangualde granitic pegmatite (Portugal) as very small (0.3 × 0.3 × 0.04 mm), pale yellow, tabular, pseudohexagonal crystals forming aggregates of subparallel individual crystals. It occurs on kryzhanovskite, frondelite, hureaulite and adularia. Rittmannite is monoclinic, space group P2/a, a 15.01(4), b 6.89(3), c 10.16(3) Å, β 112.82(25)°, V 968(4) Å3. The strongest lines in the x-ray powder-diffraction pattern [d in Å(Iobsd.)(hkl) are: 9.38 (001), 4.69 (002), 2.802 (222). Electron-microprobe data lead to the compn.: MgO 1.5, Al2O3 1.3, CaO 3.3 FeO 10.4, Fe2O3 (calcd.) 2.6, MnO 18.9, P2O5 35.9, H2O (calcd.) 19.7, total 103.6 wt.%, corresponding to the formula: (Mn0.54Ca0.47)Σ1.01Mn1.00(Fe1.152+Mn0.56Mg0.29)Σ2.00(Al1.75Ge0.25)Σ2.00(OH)2.02 (PO4)4.8H2O. The measured and calcd. d. values are 2.81(1) and 2.83 g/cm3, for Z = 2. Rittmannite is biaxial pos., with the orientation of the optical indicatrix: X//b, Z:c + 7°. No pleochroism was obsd.

E. Passaglia; G. Vezzalini ( 1988 ) - Roggianite: revised chemical formula and zeolitic properties - MINERALOGICAL MAGAZINE - n. volume 52 - pp. da 201 a 206 ISSN: 0026-461X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The holotype roggianite from Alpe Rosso (Novara, Italy) has been chemically re-analysed using modern analytical procedure (microprobe, atomic absorption,spectrophotometer, TG analyses) and tested for its zeolitic behaviour. When compared with that given in the original description, the new chemical composition shows an appreciable amount of Be and a different Si/Al ratio. An accurate powder pattern is also given. Since the mineral showed an almost complete rehydration after heating at 750°C and an appreciable ion exchange capacity, it must be considered a zeolite. It is the only zeolite with Be as fundamental constituent and with OH groups in the frameworl like partheite.

Y. Marzoni Fecia di Cossato; C. Meacci; P. Orlandi; G. Vezzalini ( 1987 ) - The second world occurrence of mopungite from the Pereta mine, Tuscany, Italy. - ATTI DELLA SOCIETÀ TOSCANA DI SCIENZE NATURALI RESIDENTE IN PISA. MEMORIE. SERIE A - n. volume 94 - pp. da 135 a 138 ISSN: 0365-7655 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Mopungite, NaSb(OH)6, from Pereta mine is reported. Few little crystals (about 0.05 mm on edge) associated with limonite, senarmontite, valentinite, gypsum, native sulphur, klebelsbergite and peretaite, occur on altered stibnite.

C. Baudracco-Gritti; S. Quartieri; G. Vezzalini; F. Permingeat; F. Pillard; R. Rinaldi ( 1987 ) - A lead-free wakefieldite-(Ce): New data on the mineral species corresponding to cerium orthovanadate - BULLETIN DE MINERALOGIE - n. volume 110 - pp. da 657 a 663 ISSN: 0180-9210 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A mineral, incorrectly called wolframite, from Tifemine (Morocco), was identified as nonplumboan wakefieldite-(Ce). This is the second occurrence of wakefieldite-(Ce) in the world and the first one which is Pb-free. The mineral occurs as black to brownish black bundles of veinlets, exhibiting a perfect cleavage, in massive white quartz. Electron microprobe anal. gave: (Ce0.52La0.18Nd0.15Y0.07Pr0.05Sm0.02)Σ0.99(V0.92As0.08)Σ1.00O4. Crystal structure refinement in space group I41/amd confirmed the hypothesis of a zircon-type structure with a 7.354(3) and c 6.488(4) Å. X-ray powder diffraction data are given. The measured and calcd. d. values are 4.76 and 4.80 g/cm3, resp. The mineral has hardness 250 kg/mm2, is stable at least up to 1050°, and is uniaxial pos. with nω 1.97(2) (translucent pale brown), nε 2.16 (almost opaque hazel brown).

C. Sabelli; G. Vezzalini ( 1987 ) - Cetineite, a new antimony oxide-sulfide mineral from Cetine mine, Tuscany, Italy - NEUES JAHRBUCH FUR MINERALOGIE MONATSHEFTE - n. volume 9 - pp. da 419 a 425 ISSN: 0028-3649 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Cetineite, a new Sb oxide-sulfide mineral, occurs as tufts of acicular orange-red crystals in slag cavities in the dumps of the Cetine mine, Tuscany, Italy. Probe anal. gives a formula very similar to (K,Na)3+x(Sb2O3)3(SbS3)(OH)x (2.8-x)-H2O, with x ≈ 0.5. The mineral is hexagonal, P63, a = 14.230(2), c = 5.579(1)Å, Z = 2. The strongest lines of the x-ray powder pattern are given. The calcd. d. is 4.21 g/cm3 and the mineral is optically uniaxial (+) with birefringence 0.059; cleavage {100}; and microhardness (VHN20) 127-156 kg/mm2. The IR spectrum is reported.

S. Quartieri; G. Vezzalini ( 1987 ) - Crystal chemistry of stilbites: structure refinements of one normal and four chemically anomalous samples - ZEOLITES - n. volume 7 - pp. da 163 a 170 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Structural refinements were performed on 4 stilbites with anomalous chem. compns. as regards the monovalent/divalent cation ratio, and a normal stilbite. The 4 anomalous samples showed, moreover, a monoclinic angle lower than that expected from an empirical correlation between monovalent cation content and β angle. In all samples the 2 cationic sites characteristic of stilbite, were found; in only 1 sample was a new cationic site localized. One site is fully occupied by Ca alone, or, with some Na, whereas the other sites are fully or partially occupied by monovalent cations only. In the 5 stilbites, different nos. of water mol. sites were localized. The frameworks, however, seem to be unaffected by the no. and compn. of extra framework sites. The small β angle of the anomalous samples was only partially explained by structural data.

A. Alberti; P. Davoli; G. Vezzalini ( 1986 ) - The crystal structure refinement of a natural mordenite - ZEITSCHRIFT FUR KRISTALLOGRAPHIE - n. volume 175 - pp. da 249 a 256 ISSN: 0044-2968 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Natural mordenite (Na1.49K2.80Mg0.04Ca2.05Sr0.05)(Al8.98Si39.13)O96.29.07H2O from Elba, Italy is orthorhombic, space group Cmc21, with a 18.094(1), b 20.516(1), and c 7.524(1) Å; Z = 1. The structure was refined in its hydrated form to Rw = 5.2%. The atom O(8) is not set on an inversion center and the T-O(8)-T angle is not constrained to 180°. The Si/Al distribution is partially ordered, with an enrichment of Al in the tetrahedra of the 4-membered ring. All Ca ions are localized in a 8-coordinated site; K ions alternate with H2O mols. in a 6-coordinated site. At. coordinates are given.

M. Mellini; P. Orlandi; G. Vezzalini ( 1986 ) - Vanadium-bearing derbylite from the Buca della Vena mine, Apuan Alps, Italy - MINERALOGICAL MAGAZINE - n. volume 50 - pp. da 328 a 331 ISSN: 0026-461X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Vanadian derbylite (vd) [102785-52-4] at the Buca della Vena mine occurs as elongate prismatic crystals, in assocn. with black anatase; in contrast, the V-free derbylite occurs as squat prismatic crystals. The vanadian derbylite contained V2O3 2.00-7.01% or 0.19-0.68 formula units V3+ per formula unit of Sb.

R. Rinaldi; G. Vezzalini ( 1985 ) - Gismondine; the detailed x-ray structure refinement of two natural samples ( - Synth., Struct., Technol. Appl. ) (Elsevier Amsterdam NLD ) - n. volume 24 - pp. da 481 a 492 ISBN: 9780444425683 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Gismondine from different localities and with Si/Al ratios of 1.06 and 1.15 are monoclinic, space group P21/c, with a 10.0198, b 10.360, c 9.830 Å, and β 92.536°; Z = 1. The final Rw = 3.9% and Rw = 3.3%, resp. The ordered Si-Al distributions and T-O distances agree with the compositional data. Details of the Si-Al distributions in the T sites were obtained by electrostatic energy calcns. One partially occupied H2O site not previously reported for gismondine was located in both crystals. Six H atoms pertaining to 3 fully occupied H2O sites were located at the proper H bond distances between H2O and framework atoms. The rest of the zeolitic H2O (∼1.4 mols. per formula unit) partially occupies, on a statistical basis, 4 more sites. All H2O mols. are at coordination distances from the only extraframework cation site. Both structures, although with a highly ordered framework, do not display the degree of ordering for the H2O mols. that one would expect, esp. for the 1st sample.

A. Alberti; G. Vezzalini; F. Cariati; L. Erre; P. Piu ( 1985 ) - Dehydration and re-hydration of the zeolites with 4-4-1 SBU's: near IR evidence for topological changes in heulandite I - ZEOLITES - n. volume 5 - pp. da 289 a 291 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Near-IR diffuse reflectance spectra show the absence of hydroxyls in natural heulandite and the presence of hydroxyls in its heat-collapsed phases B and I. These results, compared with analogous ones of barrerite and stellerite, indicated the impossibility for a framework, which has been interrupted by heat-induced dehydration, to re-form by rehydration the original topol. of the natural phase. In general, there was a direct correlation between the amt. of new T-O-T bridges and the mobility of the new framework in zeolites built by connecting 4-4-1 secondary building units.

E. Passaglia; E. Galli; G. Gottardi; G. Vezzalini ( 1985 ) - An anomalous phillipsite from Saint-Jean-le-Centenaire, Ardeche - BULLETIN DE MINERALOGIE - n. volume 108 - pp. da 719 a 724 ISSN: 0180-9210 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Phillipsite [12174-18-4] occurs as clear transparent spheroids, colorless to yellow to reddish-orange in color, in the vugs of a basalt at Saint-Jean-le-Centenaire, Ardeche, France. The fibrous radial nature of the spheroids can be obsd. under the microscope only between crossed polars. It has a higher content of Si than the normal hydrothermal (i.e. those occurring in vugs of massive rocks) phillipsites. The powder pattern lacks all those peaks which make the distinction between phillipsite and merlinoite possible. The peak broadening in the powder pattern indicates a crystallite size of ∼350 Å. This anomalous zeolite is more similar to phillipsite than to merlinoite; its features are near those of some sedimentary and some synthetic phillipsites.

E. Passaglia; G. Vezzalini ( 1985 ) - Crystal chemistry of diagenetic zeolites in volcanoclastic deposits of Italy - CONTRIBUTIONS TO MINERALOGY AND PETROLOGY - n. volume 90 - pp. da 190 a 198 ISSN: 0010-7999 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Zeolites from the most important volcanoclastic deposits of Italy include: (1) phillipsite and heulandite from the cinerite of the central northern Apennines; (2) chabazite and phillipsite from phonolitic tephritic ignimbrites contg. black pumices; (3) phillipsite from the tufo lionato of Vulcano Laziale; (4) chabazite and phillipsite from the Campanian ignimbrite; (5) phillipsite from the Neapolitan yellow tuff; and (6) chabazite and phillipsite from the pyroclastics of Monte Vulture. Compared with sedimentary phillipsites and chabazites described in the literature, the chabazites and phillipsites studied have lower Si/Al ratios and higher K contents. These chem. peculiarities are correlated with both the K-rich vesuvianitic-leucititic, latitic-phonolitic, and potassic alkali-trachytic chem. of the ash from which they were derived and, very likely, with the character of the hydrol. open system environment in which they formed. The zeolites of the heulandite-clinoptilolite group from the cinerites of the central northern Apennines is classified as a true heulandite on the basis of its chem. compn. and thermal behavior.

A. Alberti; E. Galli; G. Vezzalini ( 1985 ) - Vanadian derbylite (vd) [102785-52-4] at the Buca della Vena mine occurs as elongate prismatic crystals, in assocn. with black anatase; in contrast, the V-free derbylite occurs as squat prismatic crystals. The vanadian derbylite contained V2O3 2.00-7.01% or 0.19-0.68 formula units V3+ per formula unit of Sb. - ZEITSCHRIFT FUR KRISTALLOGRAPHIE - n. volume 173 - pp. da 257 a 265 ISSN: 0044-2968 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The refinement of the crystal structure of Theigarhorn epistilbite showed the presence of 2 tetrahedral configurations, as in the Elba dachiardite. These 2 configurations, obtained by the rotation of 2 tetrahedrons around one edge, have both C2 symmetry, with different frequency (82 and 18% resp.); thus, the resulting space group is C2. The presence of these 2 acentric domains is interpreted as a tendency to avoid the T-O-T angle of 180° present in the topol. symmetry C2/m of epistilbite. The amt. of Al, obtained from the T-O mean distance, has been cor. by a method which takes into account the influence of T-O-T angles on the measured T-O distance, and resulted in good accordance with Al content from the chem. anal. A remarkable degree of ordering in the Si/Al distribution has been found. Two extra-framework cation and 6 water mol. sites have been located. Both cation sites have a square antiprism coordination; these polyhedrons form clusters of 4 antiprisms, which are linked together as in a chessboard.

F. Guelfi; P. Orlandi; G. Vezzalini; V. Mattioli ( 1985 ) - La malayaite della Val Vigezzo (Novara) - ATTI DELLA SOCIETÀ TOSCANA DI SCIENZE NATURALI RESIDENTE IN PISA. MEMORIE. SERIE A - n. volume 92 - pp. da 255 a 258 ISSN: 0365-7655 [Articolo in rivista (262) - Articolo su rivista]
Abstract

First occurrence for Italy of well developed crystals of malayaite is reported. Its chemical formula is Ca1.04Sn0.97Si1.01O5. Refined cell parameters from XRPD are a= 7.155(2), b= 8.904(2), c= 6.642, beta= 113°2'(2).

G. Vezzalini; R. Oberti ( 1984 ) - The crystal chemistry of gismondines: the non-existence of potassium-rich gismondines - BULLETIN DE MINERALOGIE - n. volume 107 - pp. da 805 a 812 ISSN: 0180-9210 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Gismondine [12251-23-9] samples from 17 localities were analyzed by electron microprobe and thermogravimetric anal. and their unit-cell dimensions have been detd. The chem. compn. varies with narrow limits from the stoichiometric formula Ca4Al8Si8O32.18H2O. The Si/(Al + Si) ratio varies from 0.514 to 0.543; Ba, Fe, and Mg are always absent and K, Na, and Sr are low or absent. The chem. and x-ray data demonstrate the non-existence of K-rich gismondines. The K-rich anal. from the literature are explained by the frequent phillipsite-gismondine intergrowths. Unit-cell dimensions were const., and no correlation with chem. compn. has been found. The largest correlation is between 2 chem. parameters: Si/(Al + Si) and (Na + K)/(Na + K + Ca). The narrow field of chem. variability of this zeolite is attributed to the (Si,Al) ordered distribution.

G. Vezzalini ( 1984 ) - A refinement of Elba dachiardite: Opposite acentric domains simulating a centric structure - ZEITSCHRIFT FUR KRISTALLOGRAPHIE - n. volume 166 - pp. da 63 a 71 ISSN: 0044-2968 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The crystal structure of Elba dachiardite [12414-93-6] shows an unusual rotation of 2 tetrahedrons around 1 edge. This rotation gives rise to 2 configurations which have the same frequency, thus maintaining the statistical symmetry C2/m. The most probable distribution of ions indicates the presence of 2 cation sites and 5 water mols. One cation site is at the crossing of the 2 systems of channels and is 8-fold coordinated, the other is in the channel parallel to c and is 2-fold coordinated. The extra framework sites are not affected by the rotation within the framework, coordinating only the fixed framework O atoms.

A. Alberti; G. Vezzalini ( 1984 ) - Topological changes in dehydrated zeolites: breaking of T-O-T oxygen bridges ( - Oroceedings of the Sixth International Zeolite Conference ) (Butterworth Guildford, Surrey, UK GBR ) - pp. da 834 a 841 ISBN: 0408221585 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Some zeolites show heat-induced phases stable over a long period of time. This stability is a consequence of the breaking of T-O-T bridges, causing topological changesin the framework. Some zeolites whose framework are chacterized by the presence of 6R or 4-4-1 Secondary Building Units exhibit a thermal behaviour of this type. In some cases the framework of the heat-indiced pahse is topologically that of a known mineral, in others it differs from that of any know mineral. Topological changes are explained by the extraframework cation movement causing a strain on the T-O-T bridges. This favours proton attack and the consequent breaking of these bonds. The process can occur only when water is present.

A. Alberti; G. Vezzalini ( 1983 ) - The thermal behavior of heulandites: a structural study of the dehydration of Nadap [Hungary] heulandite - TMPM. TSCHERMAKS MINERALOGISCHE UND PETROGRAPHISCHE MITTEILUNGEN - n. volume 31 - pp. da 259 a 270 ISSN: 0041-3763 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Heulandite [1318-63-4] from Nadap (Hungary), characterized by an unusually high heat-induced contraction of the cell, was refined in its A and B phases. Phase A does not differ significantly from other refined heulandites. In phase B, the shift of the CS2 cation site and of the O1-O bonded to it, produces a strong rotation of the SBU around its baricentre and a pronounced zig-zag of the SBU chain. The O1 shift is strong enough to cause the statistical breaking of a T-O-T O bridge with the migration of 1 of the 2 T atoms to a new tetrahedron, which shares 3 vertices with the previously occupied one. The fourth vertex is on the mirror plane and joins 2 SBUs of adjacent layers. The data of the refined heulandite-type minerals show that the O1 shift increases with the cation content of the CS2 site. In heulandites, where the CS2 site has a high occupancy of cations with high ionic potential O breaking occurs; in clinoptilolites, where the CS2 site has a low occupancy, the O1 shift is low and breaking of the O bridge does not occur. As a consequence only heulandite shows a B phase which is stable over a long period of time.

A. Alberti; F. Cariati; L. Erre; P. Piu; G. Vezzalini ( 1983 ) - Spectroscopic investigation on the presence of hydroxyl in natural barrerite and in its collapsed phases - PHYSICS AND CHEMISTRY OF MINERALS - n. volume 9 - pp. da 189 a 191 ISSN: 0342-1791 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Barrerite, a zeolite with a stilbite-type framework, transforms on heating at 200-380 and at 380-450° into 2 new phases, called barrerite B and D, resp. After a few days, barrerite B rehydrates to barrerite C. In the B and C heat-collapsed phases, the aluminosilicate framework is interrupted by the statistical breaking of an O bridge, giving rise to 2 partially occupied face-sharing tetrahedrons. Near-IR diffuse reflectance spectra show the absence of hydroxyls in natural barrerite and the presence of hydroxyls in its heat-collapsed phases. These results confirm the hypothesis that the fourth vertex of the tetrahedrons, generated by the breaking of the O bridge, is a OH. The presence of OH-bands in phase D suggests for this phase, as in the B and C phases, the presence of interrupted O bridges.

A. Alberti; G. Vezzalini ( 1983 ) - How the structure of natrolite is modified through the heating-induced dehydration - NEUES JAHRBUCH FUR MINERALOGIE MONATSHEFTE - n. volume 1983 - pp. da 135 a 144 ISSN: 0028-3649 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Natrolite [1318-95-2], Orthorhombic with space group Fdd2, at 350-500° dehydrates and contracts to a new phase, called metanatrolite [1302-73-4], whose space group is monoclinic F2. The cell parameters of natrolite from Faeroer Islands (a = 18.29, b = 18.64, c = 6.59 Å) after heating to 350° become a = 16.01, b = 16.73, c = 6.40 Å, γ = 90° in metanatrolite. In metanatrolite, the tetrahedral chains are rotated 11° wiyh resp. to natrolite, thus producing the obsd. decrease in a and b tarameters. Rotations of each tetrahedron around an axis perpendicular to c cause twisting of the chain and thus a decrease of the c parameter. This chain-twisting is the consequence of rotation of the tetrahedra in 2 different ways, which gives rise to 2 different configurations, 1 being more frequent. In metanatrolite Na atoms occupy positions near those occupied by H2O in natrolite. One of the 2 sym. independent Na sites can be 4-, 5-, 6-, or 7-fold coordinated, depending on the 2 possible twistings of the chains, whereas the other is always 5-fold coordinated.

G. Duchi; P. Orlandi; G. Vezzalini ( 1982 ) - La Cosalite del Cantiere Falcacci di Rio Marina (Isola d'Elba) - ATTI DELLA SOCIETÀ TOSCANA DI SCIENZE NATURALI RESIDENTE IN PISA. MEMORIE. SERIE A - n. volume 89 - pp. da 141 a 144 ISSN: 0365-7655 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new occurrence of cosalite (Pb2Bi2S5) from cantiere Falcacci, Rio Marina, Elba island (Italy) is reported. The mineral, identified through XRPD has been characterized both chemically, by a microprobe analysis and optically by bireflectance determination.

A. Alberti; G. Vezzalini; E. Pecsi-Donath ( 1982 ) - Some unusual zeolites from Hungary - ACTA GEOLOGICA ACADEMIAE SCIENTIARUM HUNGARICAE - n. volume 25 - pp. da 237 a 246 ISSN: 0001-5695 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Famous Hungarian zeolite localites are newly reported to contain natrolite [1318-95-2] with a high degree of Si-Al disorder (Gulacs Hill), heulandite [1318-63-4] with anomalous thermal polymorphism (Nadap), and the rare zeolites tetranatrolite [74192-18-0] (Gulacs Hill), gonnardite [12416-09-0] (Halap Hill), and garronite [12377-07-0] (Halap Hill). Chem. analyses, cell parameters, and other mineralogical data are reported for all 5 minerals.

A. Alberti; E. Galli; G. Vezzalini; E. Passaglia; P.F. Zanazzi ( 1982 ) - Position of cations and water molecules in hydrated chabazite. Natural and sodium, calcium, strontium, and potassium-exchanged chabazites - ZEOLITES - n. volume 2 - pp. da 303 a 309 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The crystal structures of natural and hydrated Na-, Ca-, Sr-, and K-exchanged chabazite from Keller (Germany) were refined at room temp. in the R‾3m space group. The most probable distribution of ions indicates the presence of 4 cation sites; 1 at the center of the hexagonal prism, 2 in the large cage along the [111] diagonal, and the 4th near the 8-ring window which is split into 2 sites close to each other in the monovalent exchanged forms. The site at the center of the D6R is empty in the Na and K-exchanged chabazites. In this last form, 1 of the 2 sites along [111] is also empty. H2O mols. are spread over a large no. of sites, 1 with 100% occupancy, at the center of the 8-ring window, the others, normally with low occupancy, inside the large cage. Occupancies of both cation and H2O mol. sites vary greatly in the different forms.

A. Alberti; D. Pongiluppi; G. Vezzalini ( 1982 ) - The crystal chemistry of natrolite, mesolite and scolecite - NEUES JAHRBUCH FUR MINERALOGIE-ABHANDLUNGEN - n. volume 143 - pp. da 231 a 248 ISSN: 0077-7757 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Natrolite [1318-95-2], mesolite [12043-66-2], and scolecite [1319-20-6] samples were analyzed by electron microprobe and their unit cell dimensions were detd. by x-ray powder diffractometry. K, Mg, Sr, and Ba are nearly absent in these zeolites. The Si/(Si + Al + Fe3+) ratio is 0.598-0.624, its av. being similar in the 3 phases. The (Na + K)/(Mg + Ca + Sr + Ba) ratio is 0.971-1.000, 0.455-0.517, and 0.162 for natrolite, mesolite, and scolecite, resp. The narrow field of existence of these zeolites is probably due to the Si-Al order and the distribution of the exchangeable cations. In scolecite the exchangeable cations are related to the crystallog. parameters; this relation is attributed to the presence of antiphase domains when the content of exchangeable cations exceeds the theor. value of 8 atoms per unit cell. In natrolite, the strong correlation between (b-a) and c is explained by the relation existing between these parameters and the degree of disorder in the Si-Al distribution. Analogous correlations in scolecite and mesolite are interpreted in the same way.

P. Orlandi; S. Merlino; G. Duchi; G. Vezzalini ( 1981 ) - Colusite: a new occurrence and crystal chemistry - CANADIAN MINERALOGIST - n. volume 19 - pp. da 423 a 427 ISSN: 0008-4476 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new occurrence of colusite [12197-68-1] in vugs of marble quarried at Lorano, near Carrara, Apuan Alps, Italy, is reported. The tetrahedral bronze-brown crystals are cubic, space group P43n. Two different crystals of colusite were studied by x-ray diffraction and electron-microprobe methods. One crystal, with cell edge a 10.538 Å, has a compn. corresponding to Cu26V2As6S32, ,whereas the other crystal, with a 10.621 Å, has the compn. Cu26V2As4Sn2S32. Published anal. data were recalcd. on a basis of 66 atoms per unit cell. Reflectance, measured at 470, 546, 589 and 650 nm, varies 26.7-32% in air and 13.3-17.9% in oil.

A. Alberti; G. Vezzalini; V. Tazzoli ( 1981 ) - Thomsonite: a detailed refinement with cross checking by crystal energy calculations - ZEOLITES - n. volume 1 - pp. da 91 a 97 ISSN: 0144-2449 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thomsonite [12399-54-1], from Death Valley, California, is orthorhombic, space group Pncn, with a = 13.089, b = 13.047, and c = 13.218 Å. The structure was refined to a final R of 0.035. The ordering scheme for the Si-Al distribution doubles the value of the c parameter, typical of all other fibrous zeolites. The possible Si-Al distribution is discussed for samples with an Si/Al ratio >1. Two cation sites were found. One site, occupied by Ca and Na, is at the center of a regular square antiprism, which is linked to 2 equiv. polyhedrons forming a chain parallel to c. The other site, occupied by Ca and Sr, statistically distributed over 2 equiv. positions near a center of symmetry, and is 6-fold coordinated. Four H2O mols. were found at all the H atoms located. The cation distribution and the H positions were verified by electrostatic energy calcns.

A. Alberti; G. Vezzalini ( 1981 ) - A partially disordered natrolite: relationships between cell parameters and silicon-aluminum distribution - ACTA CRYSTALLOGRAPHICA. SECTION B, STRUCTURAL CRYSTALLOGRAPHY AND CRYSTAL CHEMISTRY - n. volume B37 - pp. da 781 a 788 ISSN: 0567-7408 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Natrolite, Na16Al16Si24O80.16H2O, is orthorhombic, space group Fdd2, with a 18.354(10), b 18.587(10), and c 6.608(4) Å. The structure shows a partial disorder in the (Si,Al) distribution of 30% in all the tetrahedral sites (R = 5.4, Rw = 5.2% for 463 reflections). The relation between cell parameters and the degree of disorder are discussed in relation to the present findings and to those available in the literature. There is an increase of 0.027 Å in the c parameter in going from the ordered to the disordered phase; the b - a difference, which is zero in the disordered phase, increases to 0.35 Å in the ordered one. The rotation and twisting of the tetrahedral chain, under the influence of Na, are responsible for the b - a difference.

A. Alberti; G. Vezzalini ( 1981 ) - Crystal energies and coordination of ions in partially occupied sites: dehydrated mazzite - BULLETIN DE MINERALOGIE - n. volume 104 - pp. da 5 a 9 ISSN: 0180-9210 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Crystal energy calcns. indicate that in mazzite dehydrated at 600°, the structure is more stable when the H2O mol. W(2) occupies a site located at a coordination distance from Mg rather than when it is statistically distributed over the 2 possible sites. The increase of energy due to the Mg-W(2) coordination (12 kcal/mol) is considerable although repulsion between Mg and the H atoms gives the H2O mol. a less stable orientation. The Si-Al distribution in the tetrahedra of the 6-membered rings dets. the orientation of the H2O mols.

G. Bracci; D. Dalena; P. Orlandi; G. Duchi; G. Vezzalini ( 1980 ) - Guettardite from Tuscany, Italy: a second occurrence - CANADIAN MINERALOGIST - n. volume 18 - pp. da 13 a 15 ISSN: 0008-4476 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Acicular black crystals of guettardite [12416-22-7] occur in small cavities at the Pitone marble quarry near Seravezza (Apuan Alps, Tuscany, Italy). The mineral is monoclinic with a 20.05(5), b 7.95(2), and c 8.44(2) Å, β 102°46' ± 10', space group P21/a. Reflectance values were detd. in air and in oil at various wavelengths. The Vickers hardness no. is 189. The proposed ideal formula is Pb(Sb,As)2S4, i.e., a ratio PbS:(Sb,As)2S3 = 1.

P. Orlandi; G. Bracci; D. Dalena; G. Duchi; G. Vezzalini ( 1980 ) - I minerali delle geodi della formazione marmifera di Carrara - ATTI DELLA SOCIETÀ TOSCANA DI SCIENZE NATURALI RESIDENTE IN PISA. MEMORIE. SERIE A - n. volume 87 - pp. da 93 a 124 ISSN: 0365-7655 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In this paper a complete and up-to date rewiew of the minerals occurring within the geodes of Carrara marble formation is given. For some sulphides and sulphosalts new chemical, physical and morphological data are given. The occurrence of a suite of minerals not previously known for this geological setting is pointed out.

A. Alberti; G. Vezzalini ( 1979 ) - The crystal structure of amicite, a zeolite - ACTA CRYSTALLOGRAPHICA. SECTION B, STRUCTURAL CRYSTALLOGRAPHY AND CRYSTAL CHEMISTRY - n. volume B35 - pp. da 2866 a 2869 ISSN: 0567-7408 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Amicite, K4Na4[Al8Si8O32].10H2O, is monoclinic, pseudotetragonal, space group I2, with a 10.226(1), b 10.422(1), c 9.884(1) Å, and β 88° 19(1)'. The topol. of its framework is the same as that of garronite, gismondine, and synthetic zeolite P and the structure can be described as formed by 2 untwisted double-crankshaft chains developed in 2 perpendicular directions. The Si/Al and Na/K distributions are ordered and consequently the symmetry is lowered from the topolog. symmetry of I41/amd to the real symmetry I2.

A. Alberti; G. Vezzalini ( 1979 ) - Amicite, a new natural zeolite - NEUES JAHRBUCH FUR MINERALOGIE MONATSHEFTE - n. volume 1979 (11) - pp. da 481 a 488 ISSN: 0028-3649 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new natural zeolite from Hoewenegg in Hegau (Germany) is described. Amicite [72283-44-4] has a space group I2 with a = 10.226, b = 10.422, c = 9.884 Å, and β = 88°19'. Unit-cell content K3.75Na3.61Ca0.05[Al7.86Si8.24O32].9.67 H2O results from electron microprobe and thermogravimetric analyses. On the basis of the structural topol., amicite is related to garronite and its ordered phase gismondine. The power pattern resembles that of synthetic zeolite Na-P. Amicite was found in the veins of a melilite-nephelinite rock and is assocd. with merlinoite and CaCO3.

G. Vezzalini ( 1979 ) - Second finding of nekoite - PERIODICO DI MINERALOGIA - n. volume 48 - pp. da 5 a 13 ISSN: 0369-8963 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Fibrous-radiated nekoite [32237-29-9], intimately intergrown with heulandite and apophyllite, occurs as a cavity filling in basalt from the Caxias do Sul region, Rio Grande do Sul, Brazil. Chem. analyses confirm the ideal nekoite formula, Ca3Si6O15·8H2O, of R.A.Chalmers, et al. (1962). Indexing of x-ray powder data yields the lattice parameters a 7.588(3), b 9.793(5), and c 7.339(5) Å with α 111°46' (4'), β 130°20' (3'), and γ 86°32' (2'). Thermogravimetric anal., DTA, and IR spectral data are given.Indexing

G. Vezzalini; V. Mattioli ( 1979 ) - Second finding of roggianite - PERIODICO DI MINERALOGIA - n. volume 48 - pp. da 15 a 20 ISSN: 0369-8963 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Roggianite [72979-38-5] with the ideal formula Ca16Al16Si32O104.42H2O occurs as well formed prismatic crystals (av. dimension 50 μm) within vugs of an albititic dike at Pizzo Marcio, Val Vigezzo, Novara, Italy. Assocd. minerals are bertrandite, scheelite, molybdenite, and chrysoberyl, none of which were reported at the roggianite type locality.

P. Comin-Chiaramonti; D. Pongiluppi; G. Vezzalini ( 1979 ) - Zeolites in shoshonitic volcanics of the north-eastern Azerbaijan (Iran) - BULLETIN DE MINERALOGIE - n. volume 102 - pp. da 386 a 390 ISSN: 0180-9210 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Zeolites (7 species) from 11 occurrences in the shoshonitic volcanics of the northeastern Azerbaijan (Iran) were examd. on the basis of chem. and x-ray analyses. From the available data the assemblages were the result of a low-temp. hydrothermal environment and can be related to the reaction between meteoric water and solid materials along the paths of the lava flows.

A. Alberti; G. Vezzalini ( 1978 ) - Madelung energies and cation distributions in olivine-type structures - ZEITSCHRIFT FUR KRISTALLOGRAPHIE - n. volume 147 - pp. da 167 a 175 ISSN: 0044-2968 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Madelung energies of 16 olivine-type structures of phosphates, silicates, borates and beryllates were computed for varying charges in sites M(1) and M (2). Predictions on the distributions of cations in sites M(1) and M(2) made on the basis of such energy calcns., agree with all the refinements published so far for structures of the olivine-type. The calcns. indicate a lower Madelung energy for ordered cations. Site preferences of many elements in olivine-type structures are predicted.

E. Passaglia; D. Pongiluppi; G. Vezzalini ( 1978 ) - The crystal chemistry of gmelinites - NEUES JAHRBUCH FUR MINERALOGIE MONATSHEFTE - n. volume 1978 - pp. da 310 a 324 ISSN: 0028-3649 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Gmelinite [12251-35-3] specimens were analyzed by electron microprobe and their unit-cell dimensions were detd. by x-ray powder diffractometry. Four samples showed compositional zoning, the others being highly homogeneous. The mineral compn. ranges approx. from Al7Si17O48 to Al8.4Si15.6O48. The major exchangeable cations are Na and Ca. K and Mg are present in small amts., Ba is always absent, and Sr frequently absent. The lattice parameters are strongly correlated with the exchangeable-cation content: a increases and c decreases with increasing divalent-cation content.

A. Alberti; R. Rinaldi; G. Vezzalini ( 1978 ) - Dynamics of dehydration in stilbite-type structures; stellerite phase B - PHYSICS AND CHEMISTRY OF MINERALS - n. volume 2 - pp. da 365 a 375 ISSN: 0342-1791 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Stellerite [1319-24-0], Ca8Al16Si56O144· 58H2O, exists as a collapsed phase B at 200-400°, which transforms very rapidly upon partial rehydration at room conditions, into a more stable phase C. After a much longer period of rehydration, phase C transforms into a phase with cell parameters similar to those of the natural phase. Phase B results from a rotation of the fundamental structural unit and the consequent lowering of the symmetry from Fmmm to Amma. In stellerite B, as in barrerite B and C, the aluminosilicate framework is interrupted by the statistical breaking of an O bridge. The resulting OH positions are not sym. equiv. and therefore have full freedom. This explains the different thermal behaviors of stellerite and barrerite and permits formulation of hypotheses on the dehydration dynamics of stilbite [67338-75-4].

A. Alberti; G. Vezzalini ( 1978 ) - Crystal structure of heat-collapsed phases of barrerite ( - Natural zeolites- Occurrence, Properties, Use ) (Pergamon Press London GBR ) - pp. da 85 a 98 ISBN: 0080219225 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Barrerite is orthorhombic, with space group Amma and unit cell dimensionsof a=13.643, b=18.200, c= 17.842 A. On heating at 200-380°C it transforms on a few hours to barrerite B, with s.g. Amma and unit cell dimensions of a=13.62, b=17.12, c=16.03A. After a few days barreriteB rehydrates to barrerite C, with s.g. Amma and unit cell parameters of a=13.61, b= 17.61, c= 16.24. On heating at 400-450°C barrerite transforms in a few hours to a D phase which is also orthorhombic and has parameters a=12.90, b=16.87, c=16.18A. The heat collapsed phases B and C are characterized by major changes in the framework. A statistical beaking of of an oxygen bridge gives rise to two half occupied face-sharing tetrahedra.

G. Vezzalini; A. Alberti ( 1975 ) - Zeolites from Alpe di Siusi [Italy] - RENDICONTI DELLA SOCIETÀ ITALIANA DI MINERALOGIA E PETROLOGIA - n. volume 31 - pp. da 711 a 719 ISSN: 0037-8828 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The porphyrites of the Western Dolomite zone contain the zeolites; analcime , natrolite, mesolite , thomsonite, heulandite, clinoptilolite, chabazite, mordenite, dachiardite and laumontite, each of which is described. The identification of the fibrous zeolites by powder pattern is confirmed by chem. anal. of the exchangeable cations Na, K, and Ca. Unit cell dimensions are reported for chabazite and more complete chem. and crystallog. data are given for clinoptilolite, mordenite and dachiardite. The macrocryst. occurrences of clinoptilolite and dachiardite.