Materials Data on Mn2Nb2O9 by Materials Project

Abstract

Nb2Mn2O9 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six equivalent MnO6 octahedra and a faceface with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are three shorter (1.97 Å) and three longer (2.11 Å) Nb–O bond lengths. Mn4+ is bonded to six equivalent O2- atoms to form MnO6 octahedra that share corners with six equivalent NbO6 octahedra and edges with three equivalent MnO6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Mn–O bond lengths are 1.93 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Nb5+ and two equivalent Mn4+ atoms. In the second O2- site, O2- is bonded in an L-shaped geometry to two equivalent Nb5+ atoms.