Materials Data on Ba5Nb3O3F20 by Materials Project

Abstract

Ba5Nb3O3F20 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. there are three inequivalent Ba sites. In the first Ba site, Ba is bonded in a 11-coordinate geometry to two equivalent O and nine F atoms. There are one shorter (2.79 Å) and one longer (2.93 Å) Ba–O bond lengths. There are a spread of Ba–F bond distances ranging from 2.75–3.01 Å. In the second Ba site, Ba is bonded in a 11-coordinate geometry to eleven F atoms. There are a spread of Ba–F bond distances ranging from 2.74–3.02 Å. In the third Ba site, Ba is bonded to twelve F atoms to form distorted BaF12 cuboctahedra that share edges with six equivalent NbOF6 pentagonal bipyramids and faces with two equivalent BaF12 cuboctahedra. There are six shorter (2.64 Å) and six longer (3.10 Å) Ba–F bond lengths. Nb is bonded to one O and six F atoms to form NbOF6 pentagonal bipyramids that share edges with two equivalent BaF12 cuboctahedra. The Nb–O bond length is 1.78 Å. There are a spread of Nb–F bond distances ranging from 2.04–2.14 Å. O is bonded in a distorted single-bond geometry to two equivalent Ba and one Nb atom. There are five inequivalent F sites. In the first F site, F is bonded to four Ba atoms to form a mixture of face and corner-sharing FBa4 tetrahedra. In the second F site, F is bonded in a 1-coordinate geometry to two Ba and one Nb atom. In the third F site, F is bonded in a 3-coordinate geometry to two Ba and one Nb atom. In the fourth F site, F is bonded in a distorted trigonal planar geometry to two equivalent Ba and one Nb atom. In the fifth F site, F is bonded in a 1-coordinate geometry to three Ba and one Nb atom.