Research output: Contribution to journal › Article › peer-review
Topologically prone or cation compression restricted phase transition: an example of feldspar-related SrGe2B2O8. / Gorelova, Liudmila ; Khandarkhaeva, Sayana; Yukhno, Valentina ; Krzhizhanovskaya, Maria ; Vereshchagin, Oleg ; Dubrovinsky, Leonid S.
In: Journal of Alloys and Compounds, 03.2023.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Topologically prone or cation compression restricted phase transition: an example of feldspar-related SrGe2B2O8
AU - Gorelova, Liudmila
AU - Khandarkhaeva, Sayana
AU - Yukhno, Valentina
AU - Krzhizhanovskaya, Maria
AU - Vereshchagin, Oleg
AU - Dubrovinsky, Leonid S.
PY - 2023/3
Y1 - 2023/3
N2 - The stability and phase transformation processes of SrGe2B2O8 were studied under extreme conditions (up to 960 ºC / 40 GPa) using in situ single-crystal and powder X-ray diffraction. The compound demonstrated stability up to 900 °C, when it starts to decompose to SrGe4O9 and Sr2B2Ge4O14. Under high-pressure (HP) conditions SrGe2B2O8 undergoes two phase transitions, accompanied by formation of B2O7 dimers and stepwise increasing of Ge coordination number from 4 to 6 through the 5-coordinated polyhedron. This unusual stepwise increase in the coordination number of the framework cation is consistent with the behavior of silicon in isostructural CaSi2B2O8, suggesting that certain topologies are prone to similar effects. We also assume that observed differences in HP behavior of isostructural paracelsian-like phases is caused by different compression capacities of tetrahedral cations (Si, Al, B).
AB - The stability and phase transformation processes of SrGe2B2O8 were studied under extreme conditions (up to 960 ºC / 40 GPa) using in situ single-crystal and powder X-ray diffraction. The compound demonstrated stability up to 900 °C, when it starts to decompose to SrGe4O9 and Sr2B2Ge4O14. Under high-pressure (HP) conditions SrGe2B2O8 undergoes two phase transitions, accompanied by formation of B2O7 dimers and stepwise increasing of Ge coordination number from 4 to 6 through the 5-coordinated polyhedron. This unusual stepwise increase in the coordination number of the framework cation is consistent with the behavior of silicon in isostructural CaSi2B2O8, suggesting that certain topologies are prone to similar effects. We also assume that observed differences in HP behavior of isostructural paracelsian-like phases is caused by different compression capacities of tetrahedral cations (Si, Al, B).
KW - SrGe2B2O8
KW - feldspar
KW - paracelsian
KW - danburite
KW - high-pressure
KW - high-temperature
KW - SrGe2B2O8Feldspar
KW - paracelsian
KW - danburite
KW - high-pressure
KW - high-temperature
UR - https://www.sciencedirect.com/science/article/pii/S0925838822050332
M3 - Article
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
M1 - 168642
ER -
ID: 101481877