Materials Data on CaCr2O4 by Materials Project

Abstract

CaCr2O4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.24–2.56 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.24–2.56 Å. There are four inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedra tilt angles range from 51–61°. There are a spread of Cr–O bond distances ranging from 1.98–2.21 Å. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing CrO6 octahedra. The corner-sharing octahedra tilt angles range from 51–61°. There are a spread of Cr–O bond distances ranging from 2.00–2.09 Å. In the third Cr3+ site, Cr3+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing CrO6 octahedra. The corner-sharing octahedra tilt angles range from 51–61°. There are a spread of Cr–O bond distances ranging from 2.00–2.09 Å. In the fourth Cr3+ site, Cr3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedra tilt angles range from 51–61°. There are a spread of Cr–O bond distances ranging from 1.98–2.21 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and three Cr3+ atoms to form distorted OCaCr3 trigonal pyramids that share corners with three OCa2Cr3 square pyramids, corners with two equivalent OCaCr3 trigonal pyramids, and edges with five OCa2Cr3 square pyramids. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Cr3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Cr3+ atoms. In the fourth O2- site, O2- is bonded to one Ca2+ and three Cr3+ atoms to form distorted OCaCr3 trigonal pyramids that share corners with three OCa2Cr3 square pyramids, corners with two equivalent OCaCr3 trigonal pyramids, and edges with five OCa2Cr3 square pyramids. In the fifth O2- site, O2- is bonded to two equivalent Ca2+ and three Cr3+ atoms to form OCa2Cr3 square pyramids that share corners with two equivalent OCa2Cr3 square pyramids, corners with two equivalent OCaCr3 trigonal pyramids, edges with five OCa2Cr3 square pyramids, and edges with three OCaCr3 trigonal pyramids. In the sixth O2- site, O2- is bonded to two equivalent Ca2+ and three Cr3+ atoms to form distorted OCa2Cr3 square pyramids that share corners with two equivalent OCa2Cr3 square pyramids, a cornercorner with one OCaCr3 trigonal pyramid, edges with five OCa2Cr3 square pyramids, and edges with two equivalent OCaCr3 trigonal pyramids. In the seventh O2- site, O2- is bonded to two equivalent Ca2+ and three Cr3+ atoms to form OCa2Cr3 square pyramids that share corners with two equivalent OCa2Cr3 square pyramids, corners with two equivalent OCaCr3 trigonal pyramids, edges with five OCa2Cr3 square pyramids, and edges with three OCaCr3 trigonal pyramids. In the eighth O2- site, O2- is bonded to two equivalent Ca2+ and three Cr3+ atoms to form distorted OCa2Cr3 square pyramids that share corners with two equivalent OCa2Cr3 square pyramids, a cornercorner with one OCaCr3 trigonal pyramid, edges with five OCa2Cr3 square pyramids, and edges with two equivalent OCaCr3 trigonal pyramids.