DOE OSTI2020
LiTa6O15 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. Li1+ is bonded in a 2-coordinate geometry to eight O2- atoms. There are a spread of Li–O bond distances ranging from 2.13–2.70 Å. There are six inequivalent Ta+4.83+ sites. In the first Ta+4.83+ site, Ta+4.83+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 10–36°. There are a spread of Ta–O bond distances ranging from 1.96–2.05 Å. In the second Ta+4.83+ site, Ta+4.83+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 8–40°. There are a spread of Ta–O bond distances ranging from 1.91–2.23 Å. In the third Ta+4.83+ site, Ta+4.83+ is bonded to seven O2- atoms to form TaO7 pentagonal bipyramids that share corners with two equivalent TaO7 pentagonal bipyramids and edges with four TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.94–2.17 Å. In the fourth Ta+4.83+ site, Ta+4.83+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 13–40°. There are a spread of Ta–O bond distances ranging from 1.91–2.11 Å. In the fifth Ta+4.83+ site, Ta+4.83+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and an edgeedge with one TaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 8–37°. There are a spread of Ta–O bond distances ranging from 1.92–2.17 Å. In the sixth Ta+4.83+ site, Ta+4.83+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ta–O bond distances ranging from 1.91–2.01 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta+4.83+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta+4.83+ atoms. In the third O2- site, O2- is bonded in a T-shaped geometry to one Li1+ and two equivalent Ta+4.83+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Ta+4.83+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Ta+4.83+ atoms. In the sixth O2- site, O2- is bonded to two equivalent Li1+ and two Ta+4.83+ atoms to form distorted corner-sharing OLi2Ta2 tetrahedra. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta+4.83+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta+4.83+ atoms. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ta+4.83+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to three Ta+4.83+ atoms. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Li1+ and three Ta+4.83+ atoms. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ta+4.83+ atoms. In the thirteenth O2- site, O2- is bonded in a T-shaped geometry to one Li1+ and two equivalent Ta+4.83+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Li1+ and two Ta+4.83+ atoms. In the fifteenth O2- site, O2- is bonded in a linear geometry to two equivalent Ta+4.83+ atoms.