Materials Data on LaTa3O9 by Materials Project
LaTa3O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. La3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of La–O bond distances ranging from 2.47–2.80 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to seven O2- atoms to form distorted TaO7 pentagonal bipyramids that share a cornercorner with one TaO6 octahedra, corners with two equivalent TaO7 pentagonal bipyramids, an edgeedge with one TaO6 octahedra, and edges with two equivalent TaO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There are a spread of Ta–O bond distances ranging from 1.96–2.21 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with two equivalent TaO7 pentagonal bipyramids, and edges with two equivalent TaO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 28°. There is two shorter (1.98 Å) and four longer (2.00 Å) Ta–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent La3+ 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 distorted linear geometry to one La3+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one La3+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one La3+ and two equivalent Ta5+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one La3+ and two equivalent Ta5+ atoms.