Materials Data on Fe7O8 by Materials Project

Abstract

Fe7O8 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Fe+2.29+ sites. In the first Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. All Fe–O bond lengths are 2.15 Å. In the second Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. There are two shorter (2.19 Å) and four longer (2.20 Å) Fe–O bond lengths. In the third Fe+2.29+ site, Fe+2.29+ is bonded to six equivalent O2- atoms to form edge-sharing FeO6 octahedra. All Fe–O bond lengths are 2.05 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to six Fe+2.29+ atoms to form OFe6 octahedra that share corners with six equivalent OFe6 octahedra and edges with twelve equivalent OFe5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded to five Fe+2.29+ atoms to form OFe5 square pyramids that share corners with nine equivalent OFe5 square pyramids, edges with four equivalent OFe6 octahedra, and edges with four equivalent OFe5 square pyramids.