DOI: 10.17188/1704365
title: Materials Data on Ba7Nb4MoO20 by Materials Project

description: Ba7Nb4MoO20 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are seven inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–3.08 Å. In the second Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.66–3.09 Å. In the third Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.67 Å) and three longer (2.91 Å) Ba–O bond lengths. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with seven NbO6 octahedra. There are three shorter (2.82 Å) and nine longer (2.99 Å) Ba–O bond lengths. In the fifth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with seven NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.85–2.99 Å. In the sixth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent MoO4 tetrahedra, faces with three equivalent BaO12 cuboctahedra, and faces with four NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.93–3.18 Å. In the seventh Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent NbO4 tetrahedra, faces with three equivalent BaO12 cuboctahedra, and faces with four NbO6 octahedra. There are nine shorter (3.00 Å) and three longer (3.08 Å) Ba–O bond lengths. There are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to four O2- atoms to form NbO4 tetrahedra that share corners with three equivalent BaO12 cuboctahedra. There is three shorter (1.87 Å) and one longer (1.88 Å) Nb–O bond length. In the second Nb5+ site, Nb5+ is bonded to six O2- 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 2°. There are three shorter (1.90 Å) and three longer (2.23 Å) Nb–O bond lengths. In the third Nb5+ site, Nb5+ is bonded to six O2- 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 (2.25 Å) Nb–O bond lengths. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–5°. There are three shorter (2.02 Å) and three longer (2.06 Å) Nb–O bond lengths. Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with three equivalent BaO12 cuboctahedra. All Mo–O bond lengths are 1.80 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four Ba2+ and one Mo6+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four Ba2+ and one Nb5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate 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 Nb5+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and one Mo6+ atom. In the eighth O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and one Nb5+ atom.