Materials Data on Nb2Ni4O9 by Materials Project

Abstract

Ni4Nb2O9 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.85–2.33 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six O2- atoms to form a mixture of corner, edge, and face-sharing NiO6 octahedra. The corner-sharing octahedra tilt angles range from 45–46°. There are a spread of Ni–O bond distances ranging from 1.99–2.22 Å. In the second Ni2+ site, Ni2+ is bonded to six O2- atoms to form a mixture of corner, edge, and face-sharing NiO6 octahedra. The corner-sharing octahedra tilt angles range from 45–65°. There are a spread of Ni–O bond distances ranging from 2.02–2.20 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Nb5+ and two equivalent Ni2+ atoms to form distorted ONb2Ni2 trigonal pyramids that share corners with two equivalent ONbNi4 trigonal bipyramids, corners with four ONb2Ni2 trigonal pyramids, edges with two equivalent ONbNi4 trigonal bipyramids, and edges with two ONb2Ni2 trigonal pyramids. In the second O2- site, O2- is bonded to one Nb5+ and four Ni2+ atoms to form distorted ONbNi4 trigonal bipyramids that share corners with three ONb2Ni2 trigonal pyramids, edges with two equivalent ONbNi4 trigonal bipyramids, and edges with three ONb2Ni2 trigonal pyramids. In the third O2- site, O2- is bonded to two equivalent Nb5+ and two equivalent Ni2+ atoms to form distorted ONb2Ni2 trigonal pyramids that share corners with two equivalent ONbNi4 trigonal bipyramids, corners with four equivalent ONb2Ni2 trigonal pyramids, edges with two equivalent ONbNi4 trigonal bipyramids, and edges with two equivalent ONb2Ni2 trigonal pyramids. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Nb5+ and two equivalent Ni2+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Nb5+ and three Ni2+ atoms.