Materials Data on Cr2CoSe4 by Materials Project
CoCr2Se4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six equivalent CoSe6 octahedra, edges with six equivalent CrSe6 octahedra, and a faceface with one CoSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–53°. There are a spread of Cr–Se bond distances ranging from 2.49–2.61 Å. Co2+ is bonded to six Se2- atoms to form CoSe6 octahedra that share corners with twelve equivalent CrSe6 octahedra, edges with two equivalent CoSe6 octahedra, and faces with two equivalent CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–53°. There are two shorter (2.47 Å) and four longer (2.50 Å) Co–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three equivalent Cr3+ and one Co2+ atom. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent Cr3+ and two equivalent Co2+ atoms.