Materials Data on Cr8Ga3CuSe16 by Materials Project

Abstract

Cr8CuGa3Se16 is Spinel-derived structured and crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. there are two inequivalent Cr+2.75+ sites. In the first Cr+2.75+ site, Cr+2.75+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent CuSe4 tetrahedra, corners with four GaSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.53–2.59 Å. In the second Cr+2.75+ site, Cr+2.75+ is bonded to six Se2- atoms to form CrSe6 octahedra that share a cornercorner with one CuSe4 tetrahedra, corners with five GaSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.53–2.58 Å. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with twelve CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 57–58°. All Cu–Se bond lengths are 2.47 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four equivalent Se2- atoms to form GaSe4 tetrahedra that share corners with twelve CrSe6 octahedra. The corner-sharing octahedral tilt angles are 58°. All Ga–Se bond lengths are 2.51 Å. In the second Ga3+ site, Ga3+ is bonded to four Se2- atoms to form GaSe4 tetrahedra that share corners with twelve CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There are two shorter (2.51 Å) and two longer (2.52 Å) Ga–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr+2.75+ and one Cu1+ atom. In the second Se2- site, Se2- is bonded to three Cr+2.75+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SeCr3Ga trigonal pyramids. In the third Se2- site, Se2- is bonded to three equivalent Cr+2.75+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SeCr3Ga trigonal pyramids. In the fourth Se2- site, Se2- is bonded to three equivalent Cr+2.75+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SeCr3Ga trigonal pyramids.