| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Shablinskii, Andrey
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (7/7 displayed)
- 2023Galeite, Na15(SO4)5ClF4, and Schairerite, Na21(SO4)7ClF6: Phase Transitions, Thermal Expansion and Thermal Stabilitycitations
- 2023Novel Red-Emitting BaBi2B4O10:Eu3+ Phosphors: Synthesis, Crystal Structure and Luminescencecitations
- 2022Medvedevite, KMn<sup>2+</sup>V<sup>5+</sup><sub>2</sub>O<sub>6</sub>Cl⋅2H<sub>2</sub>O, a new fumarolic mineral from the Tolbachik fissure eruption 2012–2013, Kamchatka Peninsula, Russiacitations
- 2022X-ray diffraction and Mössbauer spectroscopy study of oxoborate azoproite (Mg,Fe<sup>2+</sup>)<sub>2</sub>(Fe<sup>3+</sup>,Ti,Mg,Al)O<sub>2</sub>(BO<sub>3</sub>): an <i>in situ</i> temperature-dependent investigation (5 ≤ <i>T</i> ≤ 1650 K)citations
- 2021Low-temperature investigation of natural iron-rich oxoborates vonsenite and hulsite: thermal deformations of crystal structure, strong negative thermal expansion and cascades of magnetic transitionscitations
- 2021Dobrovolskyite, Na<sub>4</sub>Ca(SO<sub>4</sub>)<sub>3</sub>, a new fumarolic sulfate from the Great Tolbachik fissure eruption, Kamchatka Peninsula, Russiacitations
- 2020Investigation of thermal behavior of mixed-valent iron borates vonsenite and hulsite containing [OM 4] n + and [OM 5] n + oxocentred polyhedra by in situ high-temperature Mössbauer spectroscopy, X-ray diffraction and thermal analysiscitations
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article
X-ray diffraction and Mössbauer spectroscopy study of oxoborate azoproite (Mg,Fe<sup>2+</sup>)<sub>2</sub>(Fe<sup>3+</sup>,Ti,Mg,Al)O<sub>2</sub>(BO<sub>3</sub>): an <i>in situ</i> temperature-dependent investigation (5 ≤ <i>T</i> ≤ 1650 K)
Abstract
<jats:p>This work is devoted to an investigation of elemental composition, crystal structure and thermal expansion of natural oxoborate azoproite from the Tazheran massif (Siberia, Russia) in the temperature range 5–1650 K. Elemental composition was determined by energy-dispersive X-ray spectroscopy (EDX). Its empirical formula based on five oxygen atoms is (Mg<jats:sub>1.81</jats:sub>Fe<jats:sup>2+</jats:sup><jats:sub>0.19</jats:sub>)<jats:sub>∑2.00</jats:sub>(Fe<jats:sup>3+</jats:sup><jats:sub>0.36</jats:sub>Ti<jats:sub>0.26</jats:sub>Mg<jats:sub>0.26</jats:sub>Al<jats:sub>0.12</jats:sub>)<jats:sub>∑1.00</jats:sub>O<jats:sub>2</jats:sub>(BO<jats:sub>3</jats:sub>). Local environment, oxidation states and ratio of Fe atoms are determined using Mössbauer spectroscopy and compared with EDX and single-crystal X-ray diffraction (SCXRD) data. A refinement of the crystal structure from SCXRD data collected at 293 K was provided for the first time. The structure could be described both in terms of cation- and anion-centered polyhedra. It is composed of vertex- and edge-sharing metal–oxygen [<jats:italic>M</jats:italic>O<jats:sub>6</jats:sub>]<jats:italic><jats:sup>n</jats:sup></jats:italic><jats:sup>−</jats:sup> octahedra that form extended zigzag chains along the <jats:italic>a</jats:italic> axis building up a framework with the [BO<jats:sub>3</jats:sub>]<jats:sup>3−</jats:sup> triangles located in its distorted trigonal channels. From the other point of view, there are double chains consisting of oxocentred [O<jats:italic>M</jats:italic><jats:sub>4</jats:sub>]<jats:italic><jats:sup>n</jats:sup></jats:italic><jats:sup>+</jats:sup> tetrahedra and [O<jats:italic>M</jats:italic><jats:sub>5</jats:sub>]<jats:italic><jats:sup>n</jats:sup></jats:italic><jats:sup>+</jats:sup> tetragonal pyramids forming six-membered rings with the triangles in its cavities. Four non-equivalent <jats:italic>M<jats:sup>n</jats:sup></jats:italic><jats:sup>+</jats:sup> sites are occupied by cations as follows: <jats:italic>M</jats:italic>(1) (2<jats:italic>a</jats:italic>) and <jats:italic>M</jats:italic>(2) (2<jats:italic>d</jats:italic>) – Mg, <jats:italic>M</jats:italic>(3) (4<jats:italic>g</jats:italic>) – Mg and Fe<jats:sup>2+</jats:sup>, <jats:italic>M</jats:italic>(4) (4<jats:italic>h</jats:italic>) – Fe<jats:sup>3+</jats:sup>, Ti<jats:sup>4+</jats:sup>, Mg and Al<jats:sup>3+</jats:sup>. According to differential scanning calorimetry, low- and high-temperature powder X-ray diffraction (LT- and HT-XRD) data, Mössbauer spectroscopy and magnetometry data (5 ≤ <jats:italic>T</jats:italic> ≤ 1650 K), there are no phase transitions obtained in the temperature range investigated. However, some anomalies in temperature dependencies of unit-cell parameters caused by a partial Fe<jats:sup>2+</jats:sup> → Fe<jats:sup>3+</jats:sup> oxidation are found in the range 873–1173 K. Azoproite melts at a temperature higher than 1600 K. Eigenvalues of the thermal expansion tensor are calculated for the oxoborate and thermal expansion is described in comparison with its crystal structure.</jats:p>