Materials Data on Ta3(Bi2O7)2 by Materials Project
Ta3(Bi2O7)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Ta+4.67+ sites. In the first Ta+4.67+ site, Ta+4.67+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with four TaO6 octahedra, corners with two equivalent BiO7 pentagonal bipyramids, and an edgeedge with one BiO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 34–36°. There are a spread of Ta–O bond distances ranging from 1.93–2.07 Å. In the second Ta+4.67+ site, Ta+4.67+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with four equivalent TaO6 octahedra, corners with two equivalent BiO7 pentagonal bipyramids, and edges with two equivalent BiO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 34–36°. There are a spread of Ta–O bond distances ranging from 1.96–2.06 Å. There are two inequivalent Bi+3.50+ sites. In the first Bi+3.50+ site, Bi+3.50+ is bonded to seven O2- atoms to form distorted BiO7 pentagonal bipyramids that share corners with three TaO6 octahedra, edges with two TaO6 octahedra, and edges with two equivalent BiO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–44°. There are a spread of Bi–O bond distances ranging from 2.28–2.59 Å. In the second Bi+3.50+ site, Bi+3.50+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Bi–O bond distances ranging from 2.22–2.85 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ta+4.67+ and one Bi+3.50+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ta+4.67+ and three Bi+3.50+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ta+4.67+ and three Bi+3.50+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one Ta+4.67+ and three Bi+3.50+ atoms. In the fifth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Bi+3.50+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Ta+4.67+ and one Bi+3.50+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ta+4.67+ and one Bi+3.50+ atom.