Materials Data on Cr2NiSe4 by Materials Project
NiCr2Se4 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 NiSe6 octahedra, edges with six equivalent CrSe6 octahedra, and a faceface with one NiSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–53°. There are a spread of Cr–Se bond distances ranging from 2.48–2.59 Å. Ni2+ is bonded to six Se2- atoms to form NiSe6 octahedra that share corners with twelve equivalent CrSe6 octahedra, edges with two equivalent NiSe6 octahedra, and faces with two equivalent CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–53°. All Ni–Se bond lengths are 2.51 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent Cr3+ and two equivalent Ni2+ atoms. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Cr3+ and one Ni2+ atom.