Redetermination of clinobarylite, BaBe2Si2O7
Clinobarylite, ideally BaBe2Si2O7 (chemical name barium diberyllium disilicate), is a sorosilicate mineral and dimorphic with barylite. It belongs to a group of compounds characterized by the general formula BaM 2+ 2Si2O7, with M 2+ = Be, Mg, Fe, Mn, Zn, Co, or Cu, among which the Be-, Fe-, and Cu...
Published in: | Acta Crystallographica Section E Structure Reports Online |
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Main Authors: | , , |
Format: | Text |
Language: | English |
Published: |
International Union of Crystallography
2012
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Subjects: | |
Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3470124 http://www.ncbi.nlm.nih.gov/pubmed/23125568 https://doi.org/10.1107/S1600536812040457 |
Summary: | Clinobarylite, ideally BaBe2Si2O7 (chemical name barium diberyllium disilicate), is a sorosilicate mineral and dimorphic with barylite. It belongs to a group of compounds characterized by the general formula BaM 2+ 2Si2O7, with M 2+ = Be, Mg, Fe, Mn, Zn, Co, or Cu, among which the Be-, Fe-, and Cu-members have been found in nature. The crystal structure of clinobarylite has been re-examined in this study based on single-crystal X-ray diffraction data collected from a natural sample from the type locality (Khibiny Massif, Kola Peninsula, Russia). The structure of clinobarylite can be considered as a framework of BeO4 and SiO4 tetrahedra, with one of the O atoms coordinated to two Be and one Si, one coordinated to two Si, and two O atoms coordinated to one Si and one Be atom. The BeO4 tetrahedra share corners, forming chains parallel to the c axis, which are interlinked by the Si2O7 units oriented parallel to the a axis. The Ba2+ cations (site symmetry m.) are in the framework channels and are coordinated by eleven O atoms in form of an irregular polyhedron. The Si—Obr (bridging O atom, at site symmetry m.) bond length, the Si—Onbr (non-bridging O atoms) bond lengths, and the Si—O—Si angle within the Si2O7 unit are in marked contrast to the corresponding values determined in the previous study [Krivovichev et al. (2004 ▶). N. Jb. Miner. Mh. pp. 373–384]. |
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