Materials Data on Ba2Ta6Te2O21 by Materials Project
Ba2Ta6Te2O21 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 2.81–3.22 Å. There are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Ta–O bond distances ranging from 1.94–2.05 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 10–13°. There are a spread of Ta–O bond distances ranging from 1.88–2.20 Å. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–13°. There are a spread of Ta–O bond distances ranging from 1.89–2.19 Å. Te4+ is bonded in a distorted T-shaped geometry to three O2- atoms. There is one shorter (1.90 Å) and two longer (1.92 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 Ta5+, and one Te4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ta5+, and one Te4+ atom. In the third O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and two Ta5+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to one Ba2+ and two Ta5+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two Ta5+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two equivalent Ta5+ atoms.