Materials Data on CrCoAs by Materials Project

Abstract

CrCoAs crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Cr2+ is bonded to five As3- atoms to form CrAs5 square pyramids that share corners with ten equivalent CrAs5 square pyramids, corners with six equivalent CoAs4 tetrahedra, edges with six equivalent CrAs5 square pyramids, and edges with six equivalent CoAs4 tetrahedra. There are one shorter (2.51 Å) and four longer (2.58 Å) Cr–As bond lengths. Co1+ is bonded to four As3- atoms to form CoAs4 tetrahedra that share corners with six equivalent CrAs5 square pyramids, corners with ten equivalent CoAs4 tetrahedra, edges with six equivalent CrAs5 square pyramids, and edges with two equivalent CoAs4 tetrahedra. There are two shorter (2.33 Å) and two longer (2.36 Å) Co–As bond lengths. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a distorted q6 geometry to three equivalent Cr2+ and six equivalent Co1+ atoms. In the second As3- site, As3- is bonded in a 9-coordinate geometry to six equivalent Cr2+ and three equivalent Co1+ atoms.