Materials Data on Ca3Ta2O8 by Materials Project

Abstract

Ca3Ta2O8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.24–2.79 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.22–2.47 Å. Ta5+ is bonded to six O2- atoms to form distorted edge-sharing TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.92–2.13 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Ta5+ atom. In the third O2- site, O2- is bonded to three Ca2+ and one Ta5+ atom to form a mixture of distorted corner and edge-sharing OCa3Ta trigonal pyramids. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Ta5+ atoms.