Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Crystal structures of K-cymrite and kokchetavite from single-crystal X-ray diffraction. / Romanenko, Alexandr V.; Rashchenko, Sergey V.; Sokol, Alexander G. и др.
в: American Mineralogist, Том 106, № 3, 26.03.2021, стр. 404-409.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Crystal structures of K-cymrite and kokchetavite from single-crystal X-ray diffraction
AU - Romanenko, Alexandr V.
AU - Rashchenko, Sergey V.
AU - Sokol, Alexander G.
AU - Korsakov, Andrey V.
AU - Seryotkin, Yurii V.
AU - Glazyrin, Konstantin V.
AU - Musiyachenko, Kira
N1 - Publisher Copyright: © 2021 Walter de Gruyter GmbH, Berlin/Boston 2021. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/3/26
Y1 - 2021/3/26
N2 - We determined for the first time the crystal structures of high-pressure K-cymrite (KAlSi3O8·H2O) and its dehydrated form kokchetavite (KAlSi3O8) using single-crystal X-ray difraction. The K-cymrite structure has been successfully refined in the hexagonal space group P6/mmm [a = 5.3361(3) Å, c = 7.7081(7) Å, V = 190.08(3) Å3, R1 = 0.036 for 127 unique observed reflections], which is in agreement with previous models from powder X-ray difraction. In contrast, kokchetavite shows superstructural reflections, suggesting a diferent unit cell and a space group of P6/mcc [a = 10.5757(3) Å, c = 15.6404(6) Å, V = 1514.94(10) Å3, R1 = 0.068 for 1455 unique observed reflections]. Upon dehydration, single-crystal grains of K-cymrite transform into single-crystal grains of kokchetavite. The latter questions a previous interpretation of kokchetavite crystals in mineral inclusions as a product of direct crystallization from fluid/melt. The Raman spectrum of K-cymrite shows a strong polarization dependence, which is important in identification of the mineral inclusions.
AB - We determined for the first time the crystal structures of high-pressure K-cymrite (KAlSi3O8·H2O) and its dehydrated form kokchetavite (KAlSi3O8) using single-crystal X-ray difraction. The K-cymrite structure has been successfully refined in the hexagonal space group P6/mmm [a = 5.3361(3) Å, c = 7.7081(7) Å, V = 190.08(3) Å3, R1 = 0.036 for 127 unique observed reflections], which is in agreement with previous models from powder X-ray difraction. In contrast, kokchetavite shows superstructural reflections, suggesting a diferent unit cell and a space group of P6/mcc [a = 10.5757(3) Å, c = 15.6404(6) Å, V = 1514.94(10) Å3, R1 = 0.068 for 1455 unique observed reflections]. Upon dehydration, single-crystal grains of K-cymrite transform into single-crystal grains of kokchetavite. The latter questions a previous interpretation of kokchetavite crystals in mineral inclusions as a product of direct crystallization from fluid/melt. The Raman spectrum of K-cymrite shows a strong polarization dependence, which is important in identification of the mineral inclusions.
KW - K-cymrite
KW - kokchetavite
KW - Raman spectroscopy
KW - single-crystal X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=85102513690&partnerID=8YFLogxK
U2 - 10.2138/am-2020-7407
DO - 10.2138/am-2020-7407
M3 - Article
AN - SCOPUS:85102513690
VL - 106
SP - 404
EP - 409
JO - American Mineralogist
JF - American Mineralogist
SN - 0003-004X
IS - 3
ER -
ID: 28089964