Materials Data on ZnCr8Cu3Se16 by Materials Project

Abstract

Cr8Cu3ZnSe16 is Spinel-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are four inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with three equivalent CuSe4 tetrahedra, corners with three equivalent ZnSe4 tetrahedra, and edges with six CrSe6 octahedra. There are three shorter (2.51 Å) and three longer (2.54 Å) Cr–Se bond lengths. In the second Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with six CuSe4 tetrahedra and edges with six CrSe6 octahedra. All Cr–Se bond lengths are 2.53 Å. In the third Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent ZnSe4 tetrahedra, corners with four CuSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.51–2.53 Å. In the fourth Cr3+ site, Cr3+ is bonded to six Se2- atoms to form CrSe6 octahedra that share a cornercorner with one ZnSe4 tetrahedra, corners with five CuSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.51–2.53 Å. There are three inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to four 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 2.40 Å. In the second Cu2+ site, Cu2+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with twelve CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 56–57°. All Cu–Se bond lengths are 2.40 Å. In the third Cu2+ site, Cu2+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with twelve CrSe6 octahedra. The corner-sharing octahedral tilt angles are 57°. There are one shorter (2.39 Å) and three longer (2.40 Å) Cu–Se bond lengths. Zn2+ is bonded to four Se2- atoms to form ZnSe4 tetrahedra that share corners with twelve CrSe6 octahedra. The corner-sharing octahedra tilt angles range from 58–59°. All Zn–Se bond lengths are 2.45 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Cr3+ and one Zn2+ atom to form distorted corner-sharing SeZnCr3 trigonal pyramids. In the second Se2- site, Se2- is bonded to three equivalent Cr3+ and one Cu2+ atom to form distorted edge-sharing SeCr3Cu trigonal pyramids. In the third Se2- site, Se2- is bonded to three Cr3+ and one Zn2+ atom to form distorted SeZnCr3 trigonal pyramids that share corners with three SeZnCr3 trigonal pyramids and edges with three SeCr3Cu trigonal pyramids. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr3+ and one Cu2+ atom. In the fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Cr3+ and one Cu2+ atom. In the sixth Se2- site, Se2- is bonded to three equivalent Cr3+ and one Cu2+ atom to form distorted corner-sharing SeCr3Cu trigonal pyramids. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr3+ and one Cu2+ atom. In the eighth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr3+ and one Cu2+ atom.