Materials Data on CaCrO2 by Materials Project

Abstract

CaCrO2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to five O2- atoms to form distorted CaO5 trigonal bipyramids that share corners with four equivalent CaO4 tetrahedra, corners with two equivalent CrO5 trigonal bipyramids, edges with two equivalent CaO5 trigonal bipyramids, and a faceface with one CrO5 trigonal bipyramid. There are a spread of Ca–O bond distances ranging from 2.23–2.38 Å. In the second Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with two equivalent CaO4 tetrahedra, corners with four equivalent CaO5 trigonal bipyramids, corners with four equivalent CrO5 trigonal bipyramids, and an edgeedge with one CrO5 trigonal bipyramid. There are a spread of Ca–O bond distances ranging from 2.22–2.29 Å. There are two inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.00 Å) and two longer (2.17 Å) Cr–O bond lengths. In the second Cr2+ site, Cr2+ is bonded to five O2- atoms to form distorted CrO5 trigonal bipyramids that share corners with four equivalent CaO4 tetrahedra, corners with two equivalent CaO5 trigonal bipyramids, an edgeedge with one CaO4 tetrahedra, edges with two equivalent CrO5 trigonal bipyramids, and a faceface with one CaO5 trigonal bipyramid. There are a spread of Cr–O bond distances ranging from 2.08–2.29 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and three Cr2+ atoms to form distorted OCaCr3 tetrahedra that share corners with two equivalent OCaCr3 tetrahedra, corners with four equivalent OCa3Cr2 trigonal bipyramids, and edges with three OCa3Cr2 trigonal bipyramids. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Cr2+ atoms. In the third O2- site, O2- is bonded to three Ca2+ and two equivalent Cr2+ atoms to form distorted OCa3Cr2 trigonal bipyramids that share corners with four equivalent OCaCr3 tetrahedra, corners with three equivalent OCa3Cr2 trigonal bipyramids, an edgeedge with one OCaCr3 tetrahedra, and edges with three OCa3Cr2 trigonal bipyramids. In the fourth O2- site, O2- is bonded to three Ca2+ and two equivalent Cr2+ atoms to form distorted OCa3Cr2 trigonal bipyramids that share corners with three equivalent OCa3Cr2 trigonal bipyramids, edges with two equivalent OCaCr3 tetrahedra, and edges with three OCa3Cr2 trigonal bipyramids.