Materials Data on Ba2Nb6Te2O21 by Materials Project
Ba2Nb6Te2O21 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ba2+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.84–3.23 Å. There are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 8–14°. There are a spread of Nb–O bond distances ranging from 1.88–2.25 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 9–14°. There are a spread of Nb–O bond distances ranging from 1.86–2.23 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Nb–O bond distances ranging from 1.95–2.08 Å. Te4+ is bonded in a distorted T-shaped geometry to three O2- atoms. There is one shorter (1.90 Å) and two longer (1.91 Å) Te–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Nb5+, and one Te4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Nb5+, and one Te4+ atom. In the third O2- site, O2- is bonded in a linear geometry to two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and two Nb5+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to one Ba2+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two Nb5+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Nb5+ atoms.