Materials Data on Cr4GaCuSe8 by Materials Project

Abstract

Cr4CuGaSe8 is Spinel-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with three equivalent CuSe4 tetrahedra, corners with three equivalent GaSe4 tetrahedra, and edges with six equivalent CrSe6 octahedra. There are three shorter (2.51 Å) and three longer (2.58 Å) Cr–Se bond lengths. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with twelve equivalent CrSe6 octahedra. The corner-sharing octahedral tilt angles are 56°. All Cu–Se bond lengths are 2.44 Å. Ga3+ is bonded to four equivalent Se2- atoms to form GaSe4 tetrahedra that share corners with twelve equivalent CrSe6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Ga–Se bond lengths are 2.47 Å. 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 Cr3+ and one Cu1+ atom. In the second Se2- site, Se2- is bonded to three equivalent Cr3+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing SeCr3Ga trigonal pyramids.