TY - JOUR

T1 - Fluorellestadite from burned coal dumps:crystal structure refinement, vibrational spectroscopy data and thermal behavior

AU - Avdontceva, Margarita S.

AU - Zolotarev, Andrey A.

AU - Krivovichev, Sergey V.

AU - Krzhizhanovskaya, Maria G.

AU - Sokol, Ella V.

AU - Kokh, Svetlana N.

AU - Bocharov, Vladimir N.

AU - Rassomakhin, Mikhail A.

AU - Zolotarev, Anatoly A.

N1 - Funding Information: The study was supported by the Russian Foundation for Basic Research (grant № 19-05-00628). The work of E. Sokol and S. Kokh was supported through the state assignment of Institute of Geology and Mineralogy SB RAS. Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, AT part of Springer Nature. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/6

Y1 - 2021/6

N2 - Nine different samples of fluorellestadite from Chelyabinsk, Kizel and Kuznetsk coal basins were studied by single-crystal X-ray diffraction analysis, thermal X-ray diffraction (25–800 °C), Infrared (IR) and Raman spectroscopy. Fluorellestadite is hexagonal, space group P63/m, the unit-cell parameters for the nine samples studied vary within rather small ranges: a = 9.415(5) – 9.4808(7) Å, c = 6.906(2) – 6.938(8) Å, V = 530.3(4) – 538.41(9) Å3. The mineral is isotypic with apatite, the structure is based upon isolated TO4 tetrahedra, where the T position is statistically occupied by Si4+ and S6+ with the ideal ratio Si:S equal to 1:1. The fluorine atoms are located in channels of the Ca4[(S,Si)O4]6 framework oriented parallel to the c axis. The thermal expansion of fluorellestadite is almost isotropic in the temperature range 25–800 °C (for ambient temperature: αa = 12.0·10−6 °C−1, αc = 11.9·10−6 °C−1; for 800 °C: αa = 18.2·10−6 °C−1, αc = 18.6·10−6 °C−1). A similar thermal behavior had been observed for fluorapatite. Despite the same structure motifs and close conditions of formation, the samples of fluorellestadite show different S/Si/P occupancies for T site and the F/Cl/OH (X-position) ratios.

AB - Nine different samples of fluorellestadite from Chelyabinsk, Kizel and Kuznetsk coal basins were studied by single-crystal X-ray diffraction analysis, thermal X-ray diffraction (25–800 °C), Infrared (IR) and Raman spectroscopy. Fluorellestadite is hexagonal, space group P63/m, the unit-cell parameters for the nine samples studied vary within rather small ranges: a = 9.415(5) – 9.4808(7) Å, c = 6.906(2) – 6.938(8) Å, V = 530.3(4) – 538.41(9) Å3. The mineral is isotypic with apatite, the structure is based upon isolated TO4 tetrahedra, where the T position is statistically occupied by Si4+ and S6+ with the ideal ratio Si:S equal to 1:1. The fluorine atoms are located in channels of the Ca4[(S,Si)O4]6 framework oriented parallel to the c axis. The thermal expansion of fluorellestadite is almost isotropic in the temperature range 25–800 °C (for ambient temperature: αa = 12.0·10−6 °C−1, αc = 11.9·10−6 °C−1; for 800 °C: αa = 18.2·10−6 °C−1, αc = 18.6·10−6 °C−1). A similar thermal behavior had been observed for fluorapatite. Despite the same structure motifs and close conditions of formation, the samples of fluorellestadite show different S/Si/P occupancies for T site and the F/Cl/OH (X-position) ratios.

KW - apatite supergroup

KW - burned coal dumps

KW - Chelyabinsk coal basin

KW - Fluorellestadite

KW - technogenic (anthropogenic) mineralogy

UR - http://www.scopus.com/inward/record.url?scp=85101220058&partnerID=8YFLogxK

U2 - 10.1007/s00710-021-00740-4

DO - 10.1007/s00710-021-00740-4

M3 - Article

AN - SCOPUS:85101220058

VL - 115

SP - 271

EP - 281

JO - Mineralogy and Petrology

JF - Mineralogy and Petrology

SN - 0930-0708

IS - 3

ER -