Materials Data on Fe7(CoO6)2 by Materials Project

Abstract

Fe7(CoO6)2 is Spinel-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are five inequivalent Fe+2.86+ sites. In the first Fe+2.86+ site, Fe+2.86+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent CoO6 octahedra and corners with eight FeO6 octahedra. The corner-sharing octahedra tilt angles range from 53–60°. There are a spread of Fe–O bond distances ranging from 1.90–1.96 Å. In the second Fe+2.86+ site, Fe+2.86+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent CoO6 octahedra and corners with eight FeO6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. All Fe–O bond lengths are 1.94 Å. In the third Fe+2.86+ site, Fe+2.86+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent CoO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.04–2.06 Å. In the fourth Fe+2.86+ site, Fe+2.86+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent CoO6 octahedra, and edges with four FeO6 octahedra. There are two shorter (2.05 Å) and four longer (2.06 Å) Fe–O bond lengths. In the fifth Fe+2.86+ site, Fe+2.86+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with three FeO6 octahedra, and edges with three equivalent CoO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.05–2.16 Å. Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six FeO4 tetrahedra, an edgeedge with one CoO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Co–O bond distances ranging from 2.09–2.13 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe+2.86+ and one Co2+ atom. In the second O2- site, O2- is bonded to four Fe+2.86+ atoms to form distorted corner-sharing OFe4 trigonal pyramids. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe+2.86+ and one Co2+ atom. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Fe+2.86+ and two equivalent Co2+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe+2.86+ and one Co2+ atom. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Fe+2.86+ and one Co2+ atom.