DOI: 10.17188/1693275
title: Materials Data on Al4Zn3Cr2O12 by Materials Project

description: Cr2Zn3Al4O12 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six ZnO4 tetrahedra, an edgeedge with one CrO6 octahedra, and edges with five AlO6 octahedra. There are four shorter (2.01 Å) and two longer (2.02 Å) Cr–O bond lengths. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six ZnO4 tetrahedra and edges with six AlO6 octahedra. All Cr–O bond lengths are 2.02 Å. In the third Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six ZnO4 tetrahedra, edges with two equivalent CrO6 octahedra, and edges with four equivalent AlO6 octahedra. There are four shorter (2.01 Å) and two longer (2.03 Å) Cr–O bond lengths. There are three inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with five CrO6 octahedra and corners with seven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There is two shorter (1.98 Å) and two longer (1.99 Å) Zn–O bond length. In the second Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with four CrO6 octahedra and corners with eight AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–63°. There are a spread of Zn–O bond distances ranging from 1.98–2.00 Å. In the third Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three equivalent CrO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–63°. There is three shorter (1.99 Å) and one longer (2.00 Å) Zn–O bond length. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six ZnO4 tetrahedra, edges with two CrO6 octahedra, and edges with four AlO6 octahedra. There is four shorter (1.93 Å) and two longer (1.95 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six ZnO4 tetrahedra, edges with three CrO6 octahedra, and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.95 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six ZnO4 tetrahedra, edges with two equivalent CrO6 octahedra, and edges with four AlO6 octahedra. There is four shorter (1.93 Å) and two longer (1.96 Å) Al–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Cr3+, one Zn2+, and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded to one Zn2+ and three Al3+ atoms to form distorted corner-sharing OAl3Zn trigonal pyramids. In the third O2- site, O2- is bonded to one Zn2+ and three Al3+ atoms to form distorted corner-sharing OAl3Zn trigonal pyramids. In the fourth O2- site, O2- is bonded to one Cr3+, one Zn2+, and two equivalent Al3+ atoms to form distorted corner-sharing OAl2ZnCr trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Cr3+, one Zn2+, and two equivalent Al3+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Cr3+, one Zn2+, and two equivalent Al3+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Cr3+, one Zn2+, and one Al3+ atom. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Cr3+, one Zn2+, and two Al3+ atoms. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Cr3+, one Zn2+, and two Al3+ atoms.