LiSnP2O7 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(6) atom to form distorted LiO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and edges with two equivalent Sn(1)O6 octahedra. Sn(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(7) atoms to form SnO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Sn(1)O6 octahedra, and edges with two equivalent Li(1)O5 square pyramids. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Sn(1)O6 octahedra, corners with three equivalent Li(1)O5 square pyramids, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-53°. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Sn(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-54°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one 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 one Li(1), one Sn(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Sn(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Li(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Sn(1) and one P(2) atom.
LiSnP2O7 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(6) atom to form distorted LiO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and edges with two equivalent Sn(1)O6 octahedra. The Li(1)-O(1) bond length is 2.10 Å. The Li(1)-O(2) bond length is 2.25 Å. The Li(1)-O(3) bond length is 2.19 Å. The Li(1)-O(5) bond length is 2.19 Å. The Li(1)-O(6) bond length is 1.94 Å. Sn(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(7) atoms to form SnO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Sn(1)O6 octahedra, and edges with two equivalent Li(1)O5 square pyramids. The Sn(1)-O(1) bond length is 2.20 Å. The Sn(1)-O(2) bond length is 2.34 Å. The Sn(1)-O(3) bond length is 2.20 Å. The Sn(1)-O(5) bond length is 2.19 Å. There is one shorter (2.29 Å) and one longer (2.39 Å) Sn(1)-O(7) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Sn(1)O6 octahedra, corners with three equivalent Li(1)O5 square pyramids, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-53°. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(2) bond length is 1.53 Å. The P(1)-O(3) bond length is 1.55 Å. The P(1)-O(4) bond length is 1.61 Å. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Sn(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-54°. The P(2)-O(4) bond length is 1.62 Å. The P(2)-O(5) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.49 Å. The P(2)-O(7) bond length is 1.60 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one 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 one Li(1), one Sn(1), and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Sn(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Sn(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Li(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Sn(1) and one P(2) atom.