Materials Data on Ca2CrO8 by Materials Project

Abstract

Ca2CrO8 is Zircon-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Ca is bonded to eight O atoms to form distorted CaO8 hexagonal bipyramids that share corners with two equivalent CrO4 tetrahedra, edges with four equivalent CaO8 hexagonal bipyramids, and an edgeedge with one CrO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.40–2.61 Å. Cr is bonded to four O atoms to form CrO4 tetrahedra that share corners with four equivalent CaO8 hexagonal bipyramids and edges with two equivalent CaO8 hexagonal bipyramids. There is two shorter (1.65 Å) and two longer (1.67 Å) Cr–O bond length. There are six inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to two equivalent Ca and one Cr atom. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ca and one Cr atom. In the third O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent Ca and one Cr atom. In the fourth O site, O is bonded in a distorted T-shaped geometry to two equivalent Ca and one O atom. The O–O bond length is 1.34 Å. In the fifth O site, O is bonded in a trigonal planar geometry to two equivalent Ca and one O atom. The O–O bond length is 1.34 Å. In the sixth O site, O is bonded in a distorted trigonal planar geometry to two equivalent Ca and one O atom.