DOI: 10.17188/1699585
title: Materials Data on Ba4Nb2WO12 by Materials Project

description: Ba4Nb2WO12 crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent WO6 octahedra, and faces with four NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.79–2.94 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with seven BaO12 cuboctahedra, a faceface with one WO6 octahedra, and faces with six NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.75–3.00 Å. In the third Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent WO6 octahedra, faces with seven BaO12 cuboctahedra, and faces with four NbO6 octahedra. The corner-sharing octahedral tilt angles are 22°. There are a spread of Ba–O bond distances ranging from 2.87–3.23 Å. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent NbO6 octahedra, faces with seven BaO12 cuboctahedra, a faceface with one NbO6 octahedra, and faces with three equivalent WO6 octahedra. The corner-sharing octahedral tilt angles are 25°. There are a spread of Ba–O bond distances ranging from 2.83–3.17 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent NbO6 octahedra, corners with three equivalent WO6 octahedra, and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–8°. There are three shorter (1.97 Å) and three longer (2.12 Å) Nb–O bond lengths. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent NbO6 octahedra, and faces with seven BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 8°. There are three shorter (1.87 Å) and three longer (2.28 Å) Nb–O bond lengths. W6+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent NbO6 octahedra, and faces with seven BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There is three shorter (1.87 Å) and three longer (2.10 Å) W–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Nb5+, and one W6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Nb5+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one W6+ atom.