Giovanni Ferraris

Bio: Giovanni Ferraris is an academic researcher from University of Turin. The author has contributed to research in topics: Crystal structure & Catalysis. The author has an hindex of 43, co-authored 226 publications receiving 6400 citations. Previous affiliations of Giovanni Ferraris include VU University Amsterdam & Accademia Nazionale dei Lincei.

Nomenclature of amphiboles: additions and revisions to the International Mineralogical Association’s amphibole nomenclature

Abstract: The introduction of a fifth amphibole group, the Na-Ca-Mg-Fe-Mn-Li group, defined by 0.50 < B(Mg,Fe2+,Mn2+,Li) < 1.50 and 0.50 ≤ B(Ca,Na) ≤ 1.50 a.f.p.u. (atoms per formula unit), with members whittakerite and ottoliniite, has been required by recent discoveries of B(LiNa) amphiboles. This, and other new discoveries, such as sodicpedrizite (which, here, is changed slightly, but significantly, from the original idealized formula), necessitate amendments to the IMA 1997 definitions of the Mg-Fe-Mn-Li, calcic, sodic-calcic and sodic groups. The discovery of obertiite and the finding of an incompatibility in the IMA 1997 subdivision of the sodic group, requires further amendments within the sodic group. All these changes, which have IMA approval, are summarized.

Crystallography of Modular Materials

Abstract: 1. Modular series - principles and types 2. Ordered derivative structures 3. Polytypes and polytype categories 4. Application of modularity to structure description and modelling 5. Modularity at crystal scale - twinning

The standardisation of mineral group hierarchies: application to recent nomenclature proposals

Abstract: A simplified definition of a mineral group is given on the basis of structural and compositional aspects. Then a hier- archical scheme for group nomenclature and mineral classification is introduced and applied to recent nomenclature proposals. A new procedure has been put in place in order to facilitate the future proposal and naming of new mineral groups within the IMA-CNMNC framework.

Static compression and H disorder in brucite, Mg(OH)2, to 11 GPa: a powder neutron diffraction study

Abstract: Neutron diffraction data suitable for Rietveld refinements were collected on a powder sample of synthetic Mg(OH)2 by the Polaris time-of-flight spectrometer (ISIS spallation source, U.K.) at 10-4 7.8(3) and 10.9(6) GPa. The Paris-Edinburgh high-pressure cell with WC anvils was used. Pressure calibration and equation-ofstate results were attained by separate runs with an NaCl internal standard. Interpolation of p(V) data by the fourth-order Birch-Murnaghan e.o.s. yields K 0=41(2) GPa, K′0=4(2) and K″0=1.1(9) GPa-1. The bulk modulus obtained is smaller than previously reported results. Rietveld refinements (R prof =1.45% and 2.02% at 10-4 and 10.9 GPa) show that H lies on the threefold axis (1/3, 2/3, z) up to 10.9 GPa, where a model with H disordered in (x, 2x, z) can be refined. In the latter case, a hydrogen bond with O-H=0.902(7), H..O′=2.026(8) A and

Bond valence vs bond length in O…O hydrogen bonds

Abstract: The total valence of the bonds between acceptors and the H atoms bonded to a water molecule (s d) is taken equal to the bond valence (st) received by the donor 0 atom from coordination bonds. For an OH- group, s d = sr-l. Plots of the bond valence s for H...O bonds as functions of O...O, H...O and O-H distances are fitted with the function s = (R/Ro)-b+ k. The most reliable fitting is obtained for s vs O...O; a minimum value of O...O ~_2.55 A for the hydrogen bonds donated by a water molecule is predicted. Similar curves from the literature are compared and discussed.

An internally consistent thermodynamic data set for phases of petrological interest

Abstract: The thermodynamic properties of 154 mineral end-members, 13 silicate liquid end-members and 22 aqueous fluid species are presented in a revised and updated data set. The use of a temperature-dependent thermal expansion and bulk modulus, and the use of high-pressure equations of state for solids and fluids, allows calculation of mineral–fluid equilibria to 100 kbar pressure or higher. A pressure-dependent Landau model for order–disorder permits extension of disordering transitions to high pressures, and, in particular, allows the alpha–beta quartz transition to be handled more satisfactorily. Several melt end-members have been included to enable calculation of simple phase equilibria and as a first stage in developing melt mixing models in NCKFMASH. The simple aqueous species density model has been extended to enable speciation calculations and mineral solubility determination involving minerals and aqueous species at high temperatures and pressures. The data set has also been improved by incorporation of many new phase equilibrium constraints, calorimetric studies and new measurements of molar volume, thermal expansion and compressibility. This has led to a significant improvement in the level of agreement with the available experimental phase equilibria, and to greater flexibility in calculation of complex mineral equilibria. It is also shown that there is very good agreement between the data set and the most recent available calorimetric data.

Molecular Models of Hydroxide, Oxyhydroxide, and Clay Phases and the Development of a General Force Field

Abstract: The fate of chemical and radioactive wastes in the environment is related to the ability of natural phases to attenuate and immobilize contaminants through chemical sorption and precipitation processes. Our understanding of these complex processes at the atomic level is provided by a few experimental and analytical methods such as X-ray absorption and NMR spectroscopies. However, due to complexities in the structure and composition of clay and other hydrated minerals, and the inherent uncertainties of the experimental methods, it is important to apply theoretical molecular models for a fundamental atomic-level understanding, interpretation, and prediction of these phenomena. In this effort, we have developed a general force field, CLAYFF, suitable for the simulation of hydrated and multicomponent mineral systems and their interfaces with aqueous solutions. Interatomic potentials were derived from parametrizations incorporating structural and spectroscopic data for a variety of simple hydrated compounds. A...

Novel tools for visualizing and exploring intermolecular interactions in molecular crystals.

Abstract: A new way of exploring packing modes and intermolecular interactions in molecular crystals is described, using Hirshfeld surfaces to partition crystal space. These molecular Hirshfeld surfaces, so named because they derive from Hirshfeld's stockholder partitioning, divide the crystal into regions where the electron distribution of a sum of spherical atoms for the molecule (the promolecule) dominates the corresponding sum over the crystal (the procrystal). These surfaces reflect intermolecular interactions in a novel visual manner, offering a previously unseen picture of molecular shape in a crystalline environment. Surface features characteristic of different types of intermolecular interactions can be identified, and such features can be revealed by colour coding distances from the surface to the nearest atom exterior or interior to the surface, or by functions of the principal surface curvatures. These simple devices provide a striking and immediate picture of the types of interactions present, and even reflect their relative strengths from molecule to molecule. A complementary two-dimensional mapping is also presented, which summarizes quantitatively the types of intermolecular contacts experienced by molecules in the bulk and presents this information in a convenient colour plot. This paper describes the use of these tools in the compilation of a pictorial glossary of intermolecular interactions, using identifiable patterns of interaction between small molecules to rationalize the often complex mix of interactions displayed by large molecules.

An improved and extended internally consistent thermodynamic dataset for phases of petrological interest, involving a new equation of state for solids

Abstract: The thermodynamic properties of 254 end-members, including 210 mineral end-members, 18 silicate liquid end-members and 26 aqueous fluid species are presented in a revised and updated internally consistent thermodynamic data set. The PVT properties of the data set phases are now based on a modified Tait equation of state (EOS) for the solids and the Pitzer & Sterner (1995) equation for gaseous components. Thermal expansion and compressibility are linked within the modified Tait EOS (TEOS) by a thermal pressure formulation using an Einstein temperature to model the temperature dependence of both the thermal expansion and bulk modulus in a consistent way. The new EOS has led to improved fitting of the phase equilibrium experiments. Many new end-members have been added, including several deep mantle phases and, for the first time, sulphur-bearing minerals. Silicate liquid end-members are in good agreement with both phase equilibrium experiments and measured heat of melting. The new dataset considerably enhances the capabilities for thermodynamic calculation on rocks, melts and aqueous fluids under crustal to deep mantle conditions. Implementations are already available in thermocalc to take advantage of the new data set and its methodologies, as illustrated by example calculations on sapphirine-bearing equilibria, sulphur-bearing equilibria and calculations to 300 kbar and 2000 °C to extend to lower mantle conditions.

Design and Preparation of Porous Polymers

Abstract: Dingcai Wu,*,† Fei Xu,† Bin Sun,† Ruowen Fu,† Hongkun He,‡ and Krzysztof Matyjaszewski*,‡ †Materials Science Institute, Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275, People's Republic of China ‡Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States