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 BaM2+2Si2O7, with M2+ = 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].
|Original language||English (US)|
|Journal||Acta Crystallographica Section E: Structure Reports Online|
|State||Published - Oct 1 2012|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics