Materials Data on ZnCrO2 by Materials Project

Abstract

ZnCrO2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (1.98 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 ZnO4 tetrahedra, corners with two equivalent ZnO5 trigonal bipyramids, an edgeedge with one ZnO4 tetrahedra, edges with two equivalent CrO5 trigonal bipyramids, and a faceface with one ZnO5 trigonal bipyramid. There are a spread of Cr–O bond distances ranging from 2.07–2.26 Å. There are two inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to five O2- atoms to form ZnO5 trigonal bipyramids that share corners with four equivalent ZnO4 tetrahedra, corners with two equivalent CrO5 trigonal bipyramids, edges with two equivalent ZnO5 trigonal bipyramids, and a faceface with one CrO5 trigonal bipyramid. There are a spread of Zn–O bond distances ranging from 2.01–2.17 Å. In the second Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four equivalent CrO5 trigonal bipyramids, corners with four equivalent ZnO5 trigonal bipyramids, and an edgeedge with one CrO5 trigonal bipyramid. There are a spread of Zn–O bond distances ranging from 1.97–2.03 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three Cr2+ and one Zn2+ atom to form distorted OZnCr3 tetrahedra that share corners with two equivalent OZnCr3 tetrahedra, corners with four equivalent OZn3Cr2 trigonal bipyramids, and edges with three OZn3Cr2 trigonal bipyramids. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Cr2+ and two equivalent Zn2+ atoms. In the third O2- site, O2- is bonded to two equivalent Cr2+ and three Zn2+ atoms to form distorted OZn3Cr2 trigonal bipyramids that share corners with four equivalent OZnCr3 tetrahedra, corners with three equivalent OZn3Cr2 trigonal bipyramids, an edgeedge with one OZnCr3 tetrahedra, and edges with three OZn3Cr2 trigonal bipyramids. In the fourth O2- site, O2- is bonded to two equivalent Cr2+ and three Zn2+ atoms to form distorted OZn3Cr2 trigonal bipyramids that share corners with three equivalent OZn3Cr2 trigonal bipyramids, edges with two equivalent OZnCr3 tetrahedra, and edges with three OZn3Cr2 trigonal bipyramids.