Li2Ta4O11 crystallizes in the trigonal R-3c space group. Li(1) is bonded to one O(3) and three equivalent O(2) atoms to form distorted LiO4 trigonal pyramids that share corners with three equivalent Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms. In the second Ta site, Ta(2) is bonded to six equivalent O(2) atoms to form TaO6 octahedra that share corners with six equivalent Li(1)O4 trigonal pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded to one Li(1) and three equivalent Ta(1) atoms to form corner-sharing OLiTa3 tetrahedra.
Li2Ta4O11 crystallizes in the trigonal R-3c space group. Li(1) is bonded to one O(3) and three equivalent O(2) atoms to form distorted LiO4 trigonal pyramids that share corners with three equivalent Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles are 59°. The Li(1)-O(3) bond length is 2.04 Å. All Li(1)-O(2) bond lengths are 2.22 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms. Both Ta(1)-O(2) bond lengths are 1.99 Å. Both Ta(1)-O(3) bond lengths are 2.05 Å. There are two shorter (1.99 Å) and one longer (2.47 Å) Ta(1)-O(1) bond length. In the second Ta site, Ta(2) is bonded to six equivalent O(2) atoms to form TaO6 octahedra that share corners with six equivalent Li(1)O4 trigonal pyramids. All Ta(2)-O(2) bond lengths are 2.00 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded to one Li(1) and three equivalent Ta(1) atoms to form corner-sharing OLiTa3 tetrahedra.