DOI: 10.17188/1705456
title: Materials Data on MnNi7O8 by Materials Project

description: MnNi7O8 is Caswellsilverite-like structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six equivalent NiO6 octahedra and edges with twelve equivalent NiO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Mn–O bond lengths are 2.18 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six equivalent NiO6 octahedra, edges with two equivalent MnO6 octahedra, and edges with ten NiO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. All Ni–O bond lengths are 2.13 Å. In the second Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six equivalent MnO6 octahedra and edges with twelve equivalent NiO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ni–O bond lengths are 2.09 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to six equivalent Ni2+ atoms to form ONi6 octahedra that share corners with six equivalent ONi6 octahedra and edges with twelve OMnNi5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded to one Mn2+ and five Ni2+ atoms to form OMnNi5 octahedra that share corners with six OMnNi5 octahedra and edges with twelve ONi6 octahedra. The corner-sharing octahedral tilt angles are 0°. The O–Mn bond length is 2.18 Å. All O–Ni bond lengths are 2.13 Å. In the third O2- site, O2- is bonded to one Mn2+ and five Ni2+ atoms to form OMnNi5 octahedra that share corners with six OMnNi5 octahedra and edges with twelve ONi6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to one Mn2+ and five Ni2+ atoms to form OMnNi5 octahedra that share corners with six OMnNi5 octahedra and edges with twelve ONi6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are one shorter (2.09 Å) and four longer (2.13 Å) O–Ni bond lengths. In the fifth O2- site, O2- is bonded to one Mn2+ and five Ni2+ atoms to form OMnNi5 octahedra that share corners with six OMnNi5 octahedra and edges with twelve ONi6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O2- site, O2- is bonded to one Mn2+ and five Ni2+ atoms to form OMnNi5 octahedra that share corners with six OMnNi5 octahedra and edges with twelve ONi6 octahedra. The corner-sharing octahedral tilt angles are 0°. The O–Mn bond length is 2.18 Å. All O–Ni bond lengths are 2.13 Å. In the seventh O2- site, O2- is bonded to one Mn2+ and five Ni2+ atoms to form OMnNi5 octahedra that share corners with six OMnNi5 octahedra and edges with twelve ONi6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are one shorter (2.09 Å) and four longer (2.13 Å) O–Ni bond lengths. In the eighth O2- site, O2- is bonded to one Mn2+ and five Ni2+ atoms to form OMnNi5 octahedra that share corners with six OMnNi5 octahedra and edges with twelve ONi6 octahedra. The corner-sharing octahedral tilt angles are 0°. The O–Mn bond length is 2.18 Å. The O–Ni bond length is 2.09 Å.