Search

Your search keyword '"BALIC ZUNIC, T"' showing total 5 results
Start Over Author "BALIC ZUNIC, T" Topic x-ray diffraction
5 results on '"BALIC ZUNIC, T"'

3. Composition and structure of an iron-bearing, layered double hydroxide (LDH) – Green rust sodium sulphate

Author

Christiansen, B.C., Balic-Zunic, T., Petit, P.-O., Frandsen, C., Mørup, S., Geckeis, H., Katerinopoulou, A., and Stipp, S.L. Svane

Subjects
*LAYERED double hydroxides, *IRON oxides, *SODIUM sulfate, *CHEMICAL structure, *MOSSBAUER spectroscopy, *SOLUTION (Chemistry), *X-ray diffraction, *CRYSTALLOGRAPHY, *CHEMICAL kinetics, *SCANNING electron microscopy, *ATOMIC force microscopy
Abstract

Abstract: Mixed-valent Fe(II),Fe(III)-layered hydroxide, known as green rust, was synthesized from slightly basic, sodium sulphate solutions in an oxygen-free glove box. Solution conditions were monitored with pH and Eh electrodes and optimized to ensure a pure sulphate green-rust phase. The solid was characterised using Mössbauer spectroscopy, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The composition of the solution from which the green rust precipitated was established by mass and absorption spectroscopy. The sulphate form of green rust is composed of brucite-like layers with Fe(II) and Fe(III) in an ordered distribution. The interlayers contain sulphate, water and sodium in an arrangement characteristic for the nikischerite group. The crystal structure is highly disordered by stacking faults. The composition, formula and crystallographic parameters are: NaFe(II)6Fe(III)3(SO4)2(OH)18·12H2O, space group P-3, a =9.528(6)Å, c =10.968(8)Å and Z =1. Green rust sodium sulphate, , crystallizes in thin, hexagonal plates. Particles range from less than 50nm to 2μm in diameter and are 40nm thick or less. The material is redox active and reaction rates are fast. Extremely small particle size and high surface area contribute to rapid oxidation, transforming green rust to an Fe(III)-phase within minutes. [Copyright &y& Elsevier]

Published
2009
Full Text
View/download PDF

4. High-pressure crystal structure investigation of synthetic Fe2SiO4 spinel

Author

Monika Koch-Müller, Francesco Princivalle, Tonči Balić-Žunić, L. Secco, A. Dal Negro, Filippo Parisi, Fabrizio Nestola, Nestola, F, Balic-Zunic, T, Koch-Mueller, M, Secco, L, Princivalle, F, Parisi, F, Dal Negro, A, Nestola, F., Balic Zunic, T., Koch Muller, M., Secco, L., Princivalle, Francesco, Parisi, Filippo, and Dal Negro, A.

Subjects
Materials science, high pressure, X-ray diffraction, single crystal, synthetic Fe2SiO4 spinel, 010504 meteorology & atmospheric sciences, high pressure, X-ray diffraction, single crystal, synthetic Fe2SiO4 spinel, X ray diffraction, Spinel, 550 - Earth sciences, Crystal structure, engineering.material, 01 natural sciences, Crystallography, Ringwoodite, Octahedron, Geochemistry and Petrology, X-ray crystallography, engineering, Tetrahedron, Single crystal, 0105 earth and related environmental sciences, Solid solution
Abstract

The crystal structure of Fe2SiO4 spinel at room temperature was investigated at seven different pressures by X-ray diffraction, using a diamond anvil cell to examine the influence of Fe substitution on ringwoodite behaviour at high pressure. The results compared with those of a pure Mg endmember show that the substitution of Fe into the spinel structure causes only small changes in the compression rate of coordination polyhedra and the distortion of the octahedron. The data show that the compression rate for the octahedron and tetrahedron in (Mg,Fe)2SiO4 can be considered statistically equal for FeO6 and MgO6, as well as for SiO4 in both the endmembers. This shows why almost identical bulk moduli are reported along the solid solution in recent literature.

Published
2011

5. New accurate compression data for γ-Fe2SiO4

Author

L. Secco, Monika Koch-Müller, Michael N. Taran, Fabrizio Nestola, Tonci Balic-Zunic, Tiziana Boffa Ballaran, Francesco Princivalle, Lars Folke Olsen, Lars F. Lundegaard, Nestola, F., BOFFA BALLARAN, T., KOCH MÜLLER, M., BALIC ZUNIC, T., Taran, M., Olsen, L., Princivalle, Francesco, Secco, L., and Lundegaard, L.

Subjects
Diffraction, Equation of state, Materials science, 010504 meteorology & atmospheric sciences, Physics and Astronomy (miscellaneous), X ray diffraction, Thermodynamics, Single-crystal, 010502 geochemistry & geophysics, 01 natural sciences, γ-Fe2SiO4, Phase (matter), 0105 earth and related environmental sciences, Bulk modulus, Elastic propertie, Elastic properties, gamma Fe2SiO4, elastic properties, single crystal, Astronomy and Astrophysics, Compression (physics), X-ray diffraction, Crystallography, Geophysics, Space and Planetary Science, X-ray crystallography, Bulk velocity, Single crystal
Abstract

The equation of state for γ-Fe 2 SiO 4 was determined by single-crystal X-ray diffraction up to 10.2 GPa at room temperature. The pressure–volume data, measured at 10 different pressures, do not show any evidence of a phase transformation and were fit by a third-order Birch–Murnaghan equation of state. The following coefficients were refined simultaneously: V 0 = 559.44(6) A 3 , K T0 = 187.3(1.7) GPa, and K ′ = 5.5(4). This result implies that the Mg/Fe substitution along the γ-Fo–Fa join does not significantly affect the bulk modulus. The sample shows higher K ′ than other compositions along the Fo–Fa join, which generally have K ′ ∼ 4. Based on our results we can calculate the sound bulk velocity of γ-Fe 2 SiO 4 up to the pressures of the Transition Zone. Due to the larger K ′ of γ-Fe 2 SiO 4 , the difference in bulk sound velocity between the two end-members decreases with increasing pressure.

Published
2010

Catalog

Books, media, physical & digital resources
See catalog results