Materials Data on Ba5Nb2O11 by Materials Project
Ba5Nb2O9(O2) crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Ba sites. In the first Ba site, Ba is bonded to twelve O atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra and faces with six equivalent NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 3.03–3.12 Å. In the second Ba site, Ba is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Ba–O bond distances ranging from 2.59–3.28 Å. In the third Ba site, Ba is bonded in a 11-coordinate geometry to eleven O atoms. There are a spread of Ba–O bond distances ranging from 2.68–3.10 Å. Nb is bonded to six O atoms to form NbO6 octahedra that share faces with three equivalent BaO12 cuboctahedra and a faceface with one NbO6 octahedra. There are a spread of Nb–O bond distances ranging from 1.92–2.16 Å. There are six inequivalent O sites. In the first O site, O is bonded to four Ba and two equivalent Nb atoms to form a mixture of distorted face and corner-sharing OBa4Nb2 octahedra. The corner-sharing octahedra tilt angles range from 8–60°. In the second O site, O is bonded to four Ba and two equivalent Nb atoms to form a mixture of distorted face and corner-sharing OBa4Nb2 octahedra. The corner-sharing octahedra tilt angles range from 7–60°. In the third O site, O is bonded in a 6-coordinate geometry to five Ba and one O atom. The O–O bond length is 1.52 Å. In the fourth O site, O is bonded in a 1-coordinate geometry to five Ba and one Nb atom. In the fifth O site, O is bonded in a 6-coordinate geometry to five Ba and one Nb atom. In the sixth O site, O is bonded in a 1-coordinate geometry to five Ba and one Nb atom.