Materials Data on Ba4Nb3O12 by Materials Project
Ba4Nb3O12 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. there are four inequivalent Ba sites. In the first Ba site, Ba is bonded to twelve O atoms to form distorted BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, and faces with seven NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.75–3.11 Å. In the second Ba site, Ba is bonded in a 12-coordinate geometry to twelve O atoms. There are a spread of Ba–O bond distances ranging from 2.81–3.39 Å. In the third Ba site, Ba is bonded to twelve O atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with seven NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.77–2.99 Å. In the fourth Ba site, Ba is bonded to twelve O atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, and faces with five NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.96–3.09 Å. There are three inequivalent Nb sites. In the first Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with three equivalent NbO6 octahedra and faces with seven BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (1.89 Å) and three longer (2.26 Å) Nb–O bond lengths. In the second Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with three equivalent NbO6 octahedra and faces with five BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 4°. There are three shorter (1.89 Å) and three longer (2.21 Å) Nb–O bond lengths. In the third Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with seven BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–5°. All Nb–O bond lengths are 2.03 Å. There are four inequivalent O sites. In the first O site, O is bonded in a distorted linear geometry to four Ba and two Nb atoms. In the second O site, O is bonded in a distorted single-bond geometry to four Ba and one Nb atom. In the third O site, O is bonded in a distorted single-bond geometry to four Ba and one Nb atom. In the fourth O site, O is bonded in a distorted linear geometry to four Ba and two Nb atoms.