Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Temperature-induced iron oxidation in bafertisite Ba2Fe 42+ Ti2(Si2O7)2O2(OH)2F2 : X-ray diffraction and Mössbauer spectroscopy study. / Zhitova, Elena S.; Золотарев, Андрей; Krivovichev, Sergey V.; Goncharov, Alexey G.; Gabdrakhmanova, Faina A.; Vladykin, Nikolay V.; Krzhizhanovskaya, Maria G.; Shilovskikh, Vladimir V.; Vlasenko, Natalia S.; Zolotarev, Anatoly A.
в: Hyperfine Interactions, Том 238, № 1, 96, 01.11.2017.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Temperature-induced iron oxidation in bafertisite Ba2Fe 42+ Ti2(Si2O7)2O2(OH)2F2
T2 - X-ray diffraction and Mössbauer spectroscopy study
AU - Zhitova, Elena S.
AU - Золотарев, Андрей
AU - Krivovichev, Sergey V.
AU - Goncharov, Alexey G.
AU - Gabdrakhmanova, Faina A.
AU - Vladykin, Nikolay V.
AU - Krzhizhanovskaya, Maria G.
AU - Shilovskikh, Vladimir V.
AU - Vlasenko, Natalia S.
AU - Zolotarev, Anatoly A.
PY - 2017/11/1
Y1 - 2017/11/1
N2 - The high-temperature behavior of bafertisite was studied by combination of techniques in order to characterize the temperature-induced iron oxidation associated with deprotonation of an octahedral layer. The chemical formula of bafertisite from Darai-Pioz alkaline complex (Tajikistan) determined by electron-microprobe analyzes and Mössbauer spectroscopy is Ba 2.11(Fe2.702+Fe0.173+Mn 1.09Zr 0.04Na 0.03) (Ti 1.96Nb 0.07)(Si 2O7)2O2(OH 1.29 O 0.65F0.06)F2. In situ high-temperature powder X-ray diffraction revealed abrupt shift of reflections to the high-angle region and reduction of their intensity at T > 525 ∘C. The Mössbauer spectroscopy studies indicated that the crystal structure of bafertisite contains Fe in octahedral sites as predominantly ferric ions with Fe 3+/ ΣFe = 0.06, whereas bafertisite annealed at T = 600 ∘C has Fe in the same position with Fe 3+/ ΣFe up to 0.39. The differential scanning calorimetry and thermogravimetric analyzes reveal the occurrence of a broad exothermic effect at T ∼ 537 ∘C associated with the mass loss corresponding to deprotonation. Since in the studied sample of bafertisite, Fe 2+apfu strongly prevails over OH apfu, the stoichiometric (charged-balanced) high-temperature oxidized modification cannot be obtained. In the paper, the high-temperature behavior of bafertisite is discussed and compared to that of astrophyllite.
AB - The high-temperature behavior of bafertisite was studied by combination of techniques in order to characterize the temperature-induced iron oxidation associated with deprotonation of an octahedral layer. The chemical formula of bafertisite from Darai-Pioz alkaline complex (Tajikistan) determined by electron-microprobe analyzes and Mössbauer spectroscopy is Ba 2.11(Fe2.702+Fe0.173+Mn 1.09Zr 0.04Na 0.03) (Ti 1.96Nb 0.07)(Si 2O7)2O2(OH 1.29 O 0.65F0.06)F2. In situ high-temperature powder X-ray diffraction revealed abrupt shift of reflections to the high-angle region and reduction of their intensity at T > 525 ∘C. The Mössbauer spectroscopy studies indicated that the crystal structure of bafertisite contains Fe in octahedral sites as predominantly ferric ions with Fe 3+/ ΣFe = 0.06, whereas bafertisite annealed at T = 600 ∘C has Fe in the same position with Fe 3+/ ΣFe up to 0.39. The differential scanning calorimetry and thermogravimetric analyzes reveal the occurrence of a broad exothermic effect at T ∼ 537 ∘C associated with the mass loss corresponding to deprotonation. Since in the studied sample of bafertisite, Fe 2+apfu strongly prevails over OH apfu, the stoichiometric (charged-balanced) high-temperature oxidized modification cannot be obtained. In the paper, the high-temperature behavior of bafertisite is discussed and compared to that of astrophyllite.
KW - Bafertisite
KW - Deprotonation
KW - High-temperature crystal chemistry
KW - Iron oxidation
KW - Layered titanosilicates
UR - http://www.scopus.com/inward/record.url?scp=85035197053&partnerID=8YFLogxK
U2 - 10.1007/s10751-017-1468-9
DO - 10.1007/s10751-017-1468-9
M3 - Article
AN - SCOPUS:85035197053
VL - 238
JO - Hyperfine Interactions
JF - Hyperfine Interactions
SN - 0304-3843
IS - 1
M1 - 96
ER -
ID: 10354419