DOI: 10.17188/1321302
title: Materials Data on CaCrO2 by Materials Project

description: CaCrO2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four 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 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 2.26–2.36 Å. In the second Ca2+ site, Ca2+ is bonded to five O2- atoms to form distorted CaO5 trigonal bipyramids that share corners with four CrO5 trigonal bipyramids, an edgeedge with one CrO5 trigonal bipyramid, 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 2.26–2.36 Å. In the third Ca2+ site, Ca2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ca–O bond distances ranging from 2.24–2.27 Å. In the fourth Ca2+ site, Ca2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ca–O bond distances ranging from 2.25–2.28 Å. There are four inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded to five O2- atoms to form distorted CrO5 trigonal bipyramids that share corners with four CaO5 trigonal bipyramids, corners with four CrO5 trigonal bipyramids, an edgeedge with one CaO5 trigonal bipyramid, and edges with two equivalent CrO5 trigonal bipyramids. There are a spread of Cr–O bond distances ranging from 2.02–2.69 Å. In the second Cr2+ site, Cr2+ is bonded to five O2- atoms to form distorted CrO5 trigonal bipyramids that share corners with two equivalent CaO5 trigonal bipyramids, corners with two equivalent CrO5 trigonal bipyramids, 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 2.11–2.24 Å. In the third Cr2+ site, Cr2+ is bonded to five O2- atoms to form distorted CrO5 trigonal bipyramids that share corners with two equivalent CaO5 trigonal bipyramids, corners with two equivalent CrO5 trigonal bipyramids, 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 2.11–2.24 Å. In the fourth Cr2+ site, Cr2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cr–O bond distances ranging from 2.01–2.76 Å. There are eight 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 OCa3Cr2 trigonal bipyramids, and edges with three OCa3Cr2 trigonal bipyramids. In the second O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ca2+ and three Cr2+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ca2+ and three Cr2+ atoms. In the fourth 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 OCa3Cr2 trigonal bipyramids, and edges with three OCa3Cr2 trigonal bipyramids. In the fifth O2- site, O2- is bonded to three Ca2+ and two equivalent Cr2+ atoms to form distorted OCa3Cr2 trigonal bipyramids that share corners with four OCaCr3 tetrahedra, corners with three OCa3Cr2 trigonal bipyramids, an edgeedge with one OCaCr3 tetrahedra, and edges with three OCa3Cr2 trigonal bipyramids. In the sixth O2- site, O2- is bonded to three Ca2+ and two equivalent Cr2+ atoms to form distorted OCa3Cr2 trigonal bipyramids that share corners with three OCa3Cr2 trigonal bipyramids, edges with two equivalent OCaCr3 tetrahedra, and edges with three OCa3Cr2 trigonal bipyramids. In the seventh O2- site, O2- is bonded to three Ca2+ and two equivalent Cr2+ atoms to form distorted OCa3Cr2 trigonal bipyramids that share corners with four OCaCr3 tetrahedra, corners with three OCa3Cr2 trigonal bipyramids, an edgeedge with one OCaCr3 tetrahedra, and edges with three OCa3Cr2 trigonal bipyramids. In the eighth O2- site, O2- is bonded to three Ca2+ and two equivalent Cr2+ atoms to form distorted OCa3Cr2 trigonal bipyramids that share corners with three OCa3Cr2 trigonal bipyramids, edges with two equivalent OCaCr3 tetrahedra, and edges with three OCa3Cr2 trigonal bipyramids.