Materials Data on ZnCr2O4 by Materials Project

Abstract

ZnCr2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are nine inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four CrO4 tetrahedra, edges with three CrO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.99–2.04 Å. In the second Cr3+ site, Cr3+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with six CrO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–68°. There are a spread of Cr–O bond distances ranging from 1.91–2.00 Å. In the third Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with three equivalent CrO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.99–2.06 Å. In the fourth Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six CrO4 tetrahedra, edges with two equivalent CrO6 octahedra, and edges with four ZnO6 octahedra. There are one shorter (2.03 Å) and five longer (2.04 Å) Cr–O bond lengths. In the fifth Cr3+ site, Cr3+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with six CrO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–69°. There are a spread of Cr–O bond distances ranging from 1.90–2.00 Å. In the sixth Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five CrO4 tetrahedra, edges with three CrO6 octahedra, and edges with three ZnO6 octahedra. There are a spread of Cr–O bond distances ranging from 2.02–2.05 Å. In the seventh Cr3+ site, Cr3+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with six CrO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–67°. There are a spread of Cr–O bond distances ranging from 1.90–2.00 Å. In the eighth Cr3+ site, Cr3+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with six CrO6 octahedra and corners with six ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–67°. There are a spread of Cr–O bond distances ranging from 1.91–2.02 Å. In the ninth Cr3+ site, Cr3+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine CrO6 octahedra. The corner-sharing octahedra tilt angles range from 54–66°. There are a spread of Cr–O bond distances ranging from 1.92–2.05 Å. There are six inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with three ZnO6 octahedra and corners with nine CrO6 octahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Zn–O bond distances ranging from 1.98–2.05 Å. In the second Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six CrO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four CrO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.12–2.14 Å. In the third Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four CrO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five CrO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.09–2.16 Å. In the fourth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six CrO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four CrO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.12–2.14 Å. In the fifth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share corners with six CrO4 tetrahedra, edges with two ZnO6 octahedra, and edges with four equivalent CrO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.11–2.14 Å. In the sixth Zn2+ site, Zn2+ is bonded to six O2- atoms to form ZnO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five CrO4 tetrahedra, an edgeedge with one ZnO6 octahedra, and edges with five CrO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.03–2.18 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Cr3+ and two Zn2+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Cr3+ and two Zn2+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Cr3+ and two Zn2+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Cr3+ and two Zn2+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Cr3+ and two Zn2+ atoms. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Cr3+ and two Zn2+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Cr3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Zn2+ atom.