Materials Data on CaCrAsO5 by Materials Project

Abstract

CaCrAsO5 is Esseneite-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.21–2.77 Å. Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with four equivalent AsO4 tetrahedra and edges with two equivalent CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.92–2.11 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent CrO6 octahedra. The corner-sharing octahedra tilt angles range from 40–60°. There are a spread of As–O bond distances ranging from 1.70–1.77 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Cr3+, and one As5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one As5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Cr3+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Cr3+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Ca2+ and two equivalent Cr3+ atoms.