Li2Sn3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded in a 3-coordinate geometry to one O(3), one O(5), and one O(7) atom. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form SnO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. In the second Sn site, Sn(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(7) atom. 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 two equivalent Sn(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-60°. 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  a cornercorner with one Sn(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Sn(1), one Sn(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Sn(2) 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(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Sn(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Li(1), one Sn(2), and one P(2) atom.
Li2Sn3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded in a 3-coordinate geometry to one O(3), one O(5), and one O(7) atom. The Li(1)-O(3) bond length is 1.93 Å. The Li(1)-O(5) bond length is 2.26 Å. The Li(1)-O(7) bond length is 1.94 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form SnO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. Both Sn(1)-O(1) bond lengths are 2.53 Å. Both Sn(1)-O(3) bond lengths are 2.59 Å. Both Sn(1)-O(6) bond lengths are 2.43 Å. In the second Sn site, Sn(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(7) atom. The Sn(2)-O(1) bond length is 2.62 Å. The Sn(2)-O(2) bond length is 2.22 Å. The Sn(2)-O(5) bond length is 2.28 Å. The Sn(2)-O(7) bond length is 2.51 Å. 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 two equivalent Sn(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-60°. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.56 Å. The P(1)-O(3) bond length is 1.53 Å. The P(1)-O(4) bond length is 1.63 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  a cornercorner with one Sn(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. The P(2)-O(4) bond length is 1.64 Å. The P(2)-O(5) bond length is 1.56 Å. The P(2)-O(6) bond length is 1.53 Å. The P(2)-O(7) bond length is 1.53 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Sn(1), one Sn(2), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Sn(2) 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(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Sn(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Li(1), one Sn(2), and one P(2) atom.