Materials Data on CrCuSe2 by Materials Project
CuCrSe2 is Ilmenite-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with nine equivalent CuSe4 tetrahedra, edges with six equivalent CrSe6 octahedra, and a faceface with one CuSe4 tetrahedra. There are three shorter (2.52 Å) and three longer (2.63 Å) Cr–Se bond lengths. Cu1+ is bonded to four Se2- atoms to form distorted CuSe4 tetrahedra that share corners with nine equivalent CrSe6 octahedra, corners with six equivalent CuSe4 tetrahedra, and a faceface with one CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are one shorter (2.34 Å) and three longer (2.49 Å) Cu–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Cr3+ and one Cu1+ atom to form distorted corner-sharing SeCr3Cu trigonal pyramids. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to three equivalent Cr3+ and three equivalent Cu1+ atoms.