Materials Data on Fe5NiO8 by Materials Project

Abstract

Fe5NiO8 is Spinel-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Fe+2.80+ sites. In the first Fe+2.80+ site, Fe+2.80+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three equivalent NiO6 octahedra and corners with nine equivalent FeO6 octahedra. The corner-sharing octahedral tilt angles are 57°. There is three shorter (1.94 Å) and one longer (1.95 Å) Fe–O bond length. In the second Fe+2.80+ site, Fe+2.80+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent FeO4 tetrahedra, edges with two equivalent NiO6 octahedra, and edges with four equivalent FeO6 octahedra. There are four shorter (2.07 Å) and two longer (2.08 Å) Fe–O bond lengths. Ni2+ is bonded to six equivalent O2- atoms to form NiO6 octahedra that share corners with six equivalent FeO4 tetrahedra and edges with six equivalent FeO6 octahedra. All Ni–O bond lengths are 2.09 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe+2.80+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe+2.80+ and one Ni2+ atom.