Li2CoSn(PO4)2 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Li site, Li(2) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form LiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent Co(1)O5 trigonal bipyramids, edges with two equivalent Li(2)O6 octahedra, and edges with two equivalent P(2)O4 tetrahedra. Co(1) is bonded to one O(6), two equivalent O(3), and two equivalent O(4) atoms to form distorted CoO5 trigonal bipyramids that share corners with four equivalent Li(2)O6 octahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-64°. Sn(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form PO4 tetrahedra that share  an edgeedge with one Co(1)O5 trigonal bipyramid. In the second P site, P(2) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Li(2)O6 octahedra, corners with three equivalent Co(1)O5 trigonal bipyramids, and edges with two equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Sn(1), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Li(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Co(1), one Sn(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(2), one Co(1), one Sn(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Li(2), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to two equivalent Li(2), one Co(1), and one P(2) atom.
Li2CoSn(PO4)2 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Li(1)-O(1) bond lengths are 2.02 Å. Both Li(1)-O(2) bond lengths are 2.16 Å. In the second Li site, Li(2) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form LiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with four equivalent Co(1)O5 trigonal bipyramids, edges with two equivalent Li(2)O6 octahedra, and edges with two equivalent P(2)O4 tetrahedra. Both Li(2)-O(4) bond lengths are 2.07 Å. Both Li(2)-O(5) bond lengths are 2.36 Å. Both Li(2)-O(6) bond lengths are 2.13 Å. Co(1) is bonded to one O(6), two equivalent O(3), and two equivalent O(4) atoms to form distorted CoO5 trigonal bipyramids that share corners with four equivalent Li(2)O6 octahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-64°. The Co(1)-O(6) bond length is 2.07 Å. Both Co(1)-O(3) bond lengths are 2.18 Å. Both Co(1)-O(4) bond lengths are 2.03 Å. Sn(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(3), and two equivalent O(4) atoms. The Sn(1)-O(1) bond length is 2.58 Å. The Sn(1)-O(5) bond length is 2.46 Å. Both Sn(1)-O(3) bond lengths are 2.29 Å. Both Sn(1)-O(4) bond lengths are 2.75 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form PO4 tetrahedra that share  an edgeedge with one Co(1)O5 trigonal bipyramid. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(2) bond length is 1.53 Å. Both P(1)-O(3) bond lengths are 1.59 Å. In the second P site, P(2) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Li(2)O6 octahedra, corners with three equivalent Co(1)O5 trigonal bipyramids, and edges with two equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. The P(2)-O(5) bond length is 1.54 Å. The P(2)-O(6) bond length is 1.57 Å. Both P(2)-O(4) bond lengths are 1.57 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Sn(1), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Li(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Co(1), one Sn(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(2), one Co(1), one Sn(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Li(2), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to two equivalent Li(2), one Co(1), and one P(2) atom.