Li10Si(PSe6)2 crystallizes in the tetragonal P4_2mc space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one Se(1), one Se(4), one Se(5), and one Se(6) atom. In the second Li site, Li(2) is bonded to two equivalent Se(1), two equivalent Se(3), and two equivalent Se(5) atoms to form LiSe6 octahedra that share corners with two equivalent P(2)Se4 tetrahedra and edges with two equivalent P(1)Se4 tetrahedra. In the third Li site, Li(3) is bonded to two equivalent Se(2), two equivalent Se(4), and two equivalent Se(6) atoms to form distorted LiSe6 octahedra that share corners with two equivalent P(2)Se4 tetrahedra and edges with two equivalent Si(1)Se4 tetrahedra. In the fourth Li site, Li(4) is bonded in a 5-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), and one Se(6) atom. Si(1) is bonded to two equivalent Se(4) and two equivalent Se(6) atoms to form SiSe4 tetrahedra that share edges with two equivalent Li(3)Se6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent Se(3) and two equivalent Se(5) atoms to form PSe4 tetrahedra that share edges with two equivalent Li(2)Se6 octahedra. In the second P site, P(2) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form PSe4 tetrahedra that share corners with two equivalent Li(2)Se6 octahedra and corners with two equivalent Li(3)Se6 octahedra. The corner-sharing octahedral tilt angles range from 43-50°. There are six inequivalent Se sites. In the first Se site, Se(3) is bonded to one Li(2), two equivalent Li(4), and one P(1) atom to form a mixture of corner and edge-sharing SeLi3P trigonal pyramids. In the second Se site, Se(4) is bonded in a distorted hexagonal planar geometry to one Li(3), two equivalent Li(1), two equivalent Li(4), and one Si(1) atom. In the third Se site, Se(5) is bonded in a rectangular see-saw-like geometry to one Li(2), two equivalent Li(1), and one P(1) atom. In the fourth Se site, Se(6) is bonded in a 6-coordinate geometry to one Li(3), two equivalent Li(1), two equivalent Li(4), and one Si(1) atom. In the fifth Se site, Se(1) is bonded in a 6-coordinate geometry to one Li(2), two equivalent Li(1), two equivalent Li(4), and one P(2) atom. In the sixth Se site, Se(2) is bonded to one Li(3), two equivalent Li(4), and one P(2) atom to form distorted corner-sharing SeLi3P trigonal pyramids.
Li10Si(PSe6)2 crystallizes in the tetragonal P4_2mc space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one Se(1), one Se(4), one Se(5), and one Se(6) atom. The Li(1)-Se(1) bond length is 2.64 Å. The Li(1)-Se(4) bond length is 2.85 Å. The Li(1)-Se(5) bond length is 2.57 Å. The Li(1)-Se(6) bond length is 2.52 Å. In the second Li site, Li(2) is bonded to two equivalent Se(1), two equivalent Se(3), and two equivalent Se(5) atoms to form LiSe6 octahedra that share corners with two equivalent P(2)Se4 tetrahedra and edges with two equivalent P(1)Se4 tetrahedra. Both Li(2)-Se(1) bond lengths are 2.81 Å. Both Li(2)-Se(3) bond lengths are 2.76 Å. Both Li(2)-Se(5) bond lengths are 2.83 Å. In the third Li site, Li(3) is bonded to two equivalent Se(2), two equivalent Se(4), and two equivalent Se(6) atoms to form distorted LiSe6 octahedra that share corners with two equivalent P(2)Se4 tetrahedra and edges with two equivalent Si(1)Se4 tetrahedra. Both Li(3)-Se(2) bond lengths are 2.93 Å. Both Li(3)-Se(4) bond lengths are 2.73 Å. Both Li(3)-Se(6) bond lengths are 2.78 Å. In the fourth Li site, Li(4) is bonded in a 5-coordinate geometry to one Se(1), one Se(2), one Se(3), one Se(4), and one Se(6) atom. The Li(4)-Se(1) bond length is 3.05 Å. The Li(4)-Se(2) bond length is 2.51 Å. The Li(4)-Se(3) bond length is 2.61 Å. The Li(4)-Se(4) bond length is 2.78 Å. The Li(4)-Se(6) bond length is 3.07 Å. Si(1) is bonded to two equivalent Se(4) and two equivalent Se(6) atoms to form SiSe4 tetrahedra that share edges with two equivalent Li(3)Se6 octahedra. Both Si(1)-Se(4) bond lengths are 2.32 Å. Both Si(1)-Se(6) bond lengths are 2.30 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent Se(3) and two equivalent Se(5) atoms to form PSe4 tetrahedra that share edges with two equivalent Li(2)Se6 octahedra. Both P(1)-Se(3) bond lengths are 2.25 Å. Both P(1)-Se(5) bond lengths are 2.22 Å. In the second P site, P(2) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form PSe4 tetrahedra that share corners with two equivalent Li(2)Se6 octahedra and corners with two equivalent Li(3)Se6 octahedra. The corner-sharing octahedral tilt angles range from 43-50°. Both P(2)-Se(1) bond lengths are 2.24 Å. Both P(2)-Se(2) bond lengths are 2.22 Å. There are six inequivalent Se sites. In the first Se site, Se(3) is bonded to one Li(2), two equivalent Li(4), and one P(1) atom to form a mixture of corner and edge-sharing SeLi3P trigonal pyramids. In the second Se site, Se(4) is bonded in a distorted hexagonal planar geometry to one Li(3), two equivalent Li(1), two equivalent Li(4), and one Si(1) atom. In the third Se site, Se(5) is bonded in a rectangular see-saw-like geometry to one Li(2), two equivalent Li(1), and one P(1) atom. In the fourth Se site, Se(6) is bonded in a 6-coordinate geometry to one Li(3), two equivalent Li(1), two equivalent Li(4), and one Si(1) atom. In the fifth Se site, Se(1) is bonded in a 6-coordinate geometry to one Li(2), two equivalent Li(1), two equivalent Li(4), and one P(2) atom. In the sixth Se site, Se(2) is bonded to one Li(3), two equivalent Li(4), and one P(2) atom to form distorted corner-sharing SeLi3P trigonal pyramids.