Materials Data on Zn5Cr20(GaSe10)4 by Materials Project
Cr20Zn5(GaSe10)4 is Spinel-derived structured and crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. there are five inequivalent Cr+2.90+ sites. In the first Cr+2.90+ site, Cr+2.90+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent ZnSe4 tetrahedra, corners with three equivalent GaSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.50–2.61 Å. In the second Cr+2.90+ site, Cr+2.90+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent GaSe4 tetrahedra, corners with four ZnSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.54–2.57 Å. In the third Cr+2.90+ site, Cr+2.90+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent ZnSe4 tetrahedra, corners with three equivalent GaSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.50–2.61 Å. In the fourth Cr+2.90+ site, Cr+2.90+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent GaSe4 tetrahedra, corners with three ZnSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.51–2.59 Å. In the fifth Cr+2.90+ site, Cr+2.90+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent GaSe4 tetrahedra, corners with four ZnSe4 tetrahedra, and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.54–2.57 Å. There are two inequivalent Zn2+ sites. In the first Zn2+ site, 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 57–58°. All Zn–Se bond lengths are 2.49 Å. In the second Zn2+ site, Zn2+ is bonded to four equivalent Se2- atoms to form ZnSe4 tetrahedra that share corners with twelve CrSe6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Zn–Se bond lengths are 2.50 Å. 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 58–60°. There are one shorter (2.49 Å) and three longer (2.50 Å) Ga–Se bond lengths. There are ten inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr+2.90+ and one Zn2+ atom. In the second Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Cr+2.90+ atoms. In the third Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr+2.90+ and one Zn2+ atom. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr+2.90+ and one Zn2+ atom. In the fifth Se2- site, Se2- is bonded to three equivalent Cr+2.90+ and one Zn2+ atom to form distorted SeZnCr3 trigonal pyramids that share corners with nine SeCr3Ga trigonal pyramids and edges with three equivalent SeZnCr3 trigonal pyramids. In the sixth Se2- site, Se2- is bonded to three Cr+2.90+ and one Ga3+ atom to form distorted SeCr3Ga trigonal pyramids that share corners with six SeZnCr3 trigonal pyramids and edges with three SeCr3Ga trigonal pyramids. In the seventh Se2- site, Se2- is bonded to three equivalent Cr+2.90+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SeCr3Ga trigonal pyramids. In the eighth Se2- site, Se2- is bonded to three Cr+2.90+ and one Ga3+ atom to form distorted SeCr3Ga trigonal pyramids that share corners with six SeZnCr3 trigonal pyramids and edges with three SeCr3Ga trigonal pyramids. In the ninth Se2- site, Se2- is bonded to three Cr+2.90+ and one Ga3+ atom to form a mixture of distorted corner and edge-sharing SeCr3Ga trigonal pyramids. In the tenth Se2- site, Se2- is bonded to three Cr+2.90+ and one Zn2+ atom to form distorted SeZnCr3 trigonal pyramids that share corners with six SeZnCr3 trigonal pyramids and edges with three SeCr3Ga trigonal pyramids.