Materials Data on BaTa6O16 by Materials Project
BaTa6O16 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–2.91 Å. There are four inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to seven O2- atoms to form TaO7 pentagonal bipyramids that share corners with two equivalent TaO7 pentagonal bipyramids and edges with five TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.96–2.15 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 2–44°. There are a spread of Ta–O bond distances ranging from 1.96–2.08 Å. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 7–44°. There are a spread of Ta–O bond distances ranging from 1.96–2.01 Å. In the fourth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 18–38°. There are a spread of Ta–O bond distances ranging from 1.89–2.13 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ta5+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two equivalent Ta5+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the ninth O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the tenth O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and two equivalent Ta5+ atoms.