Materials Data on Zn2Cr3GaSe8 by Materials Project

Cr3Zn2GaSe8 is Spinel-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six equivalent ZnSe4 tetrahedra, edges with two equivalent GaSe6 octahedra, and edges with four equivalent CrSe6 octahedra. There are four shorter (2.55 Å) and two longer (2.56 Å) Cr–Se bond lengths. Zn2+ is bonded to four Se2- atoms to form ZnSe4 tetrahedra that share corners with three equivalent GaSe6 octahedra and corners with nine equivalent CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are three shorter (2.49 Å) and one longer (2.51 Å) Zn–Se bond lengths. Ga3+ is bonded to six equivalent Se2- atoms to form GaSe6 octahedra that share corners with six equivalent ZnSe4 tetrahedra and edges with six equivalent CrSe6 octahedra. All Ga–Se bond lengths are 2.60 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Cr3+ and one Zn2+ atom to form distorted SeZnCr3 trigonal pyramids that share corners with twelve SeZnCr3 trigonal pyramids and edges with three equivalent SeZnCr2Ga trigonal pyramids. In the second Se2- site, Se2- is bonded to two equivalent Cr3+, one Zn2+, and one Ga3+ atom to form a mixture of distorted edge and corner-sharing SeZnCr2Ga trigonal pyramids.