Materials Data on Cr3Cu2NiSe8 by Materials Project

Abstract

Cr3NiCu2Se8 is Spinel-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cr4+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six equivalent CuSe4 tetrahedra, edges with two equivalent NiSe6 octahedra, and edges with four equivalent CrSe6 octahedra. All Cr–Se bond lengths are 2.50 Å. Ni2+ is bonded to six equivalent Se2- atoms to form NiSe6 octahedra that share corners with six equivalent CuSe4 tetrahedra and edges with six equivalent CrSe6 octahedra. All Ni–Se bond lengths are 2.49 Å. Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with three equivalent NiSe6 octahedra and corners with nine equivalent CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 57–58°. There are three shorter (2.38 Å) and one longer (2.39 Å) Cu–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Cr4+ and one Cu1+ atom. In the second Se2- site, Se2- is bonded to two equivalent Cr4+, one Ni2+, and one Cu1+ atom to form a mixture of distorted corner and edge-sharing SeCr2CuNi trigonal pyramids.