Materials Data on Nb3AgO8 by Materials Project

Abstract

AgNb3O8 crystallizes in the orthorhombic Ibam space group. The structure is three-dimensional. there are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to seven O2- atoms to form distorted NbO7 pentagonal bipyramids that share corners with two equivalent NbO8 hexagonal bipyramids, corners with two equivalent NbO7 pentagonal bipyramids, edges with two equivalent NbO8 hexagonal bipyramids, and edges with two equivalent NbO7 pentagonal bipyramids. There are a spread of Nb–O bond distances ranging from 1.87–2.40 Å. In the second Nb5+ site, Nb5+ is bonded to eight O2- atoms to form distorted NbO8 hexagonal bipyramids that share corners with four equivalent NbO7 pentagonal bipyramids, edges with two equivalent NbO8 hexagonal bipyramids, and edges with four equivalent NbO7 pentagonal bipyramids. There are four shorter (2.11 Å) and four longer (2.12 Å) Nb–O bond lengths. Ag1+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.49 Å) and four longer (2.79 Å) Ag–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to three Nb5+ and one Ag1+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Nb5+ and two equivalent Ag1+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three Nb5+ atoms.