Materials Data on Cr2FeO4 by Materials Project
FeCr2O4 is Spinel-like structured and crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with six equivalent CrO6 octahedra and corners with six equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 52–69°. There is two shorter (1.93 Å) and two longer (2.00 Å) Cr–O bond length. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six equivalent CrO4 tetrahedra, edges with two equivalent CrO6 octahedra, and edges with four equivalent FeO6 octahedra. There are two shorter (2.04 Å) and four longer (2.05 Å) Cr–O bond lengths. Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent CrO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with four equivalent CrO6 octahedra. There are two shorter (2.13 Å) and four longer (2.14 Å) Fe–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Cr3+ and two equivalent Fe2+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Cr3+ and one Fe2+ atom.