Sn2P3O10 crystallizes in the monoclinic P2_1/m space group. Sn(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form SnO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  an edgeedge with one Sn(1)O5 square pyramid. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(6), one O(7), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Sn(1)O5 square pyramids,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one P(3)O4 tetrahedra. In the second P site, P(2) is bonded to one O(4), one O(7), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Sn(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. In the third P site, P(3) is bonded to one O(2), one O(6), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with four equivalent Sn(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Sn(1) and one P(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sn(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Sn(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(3) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.
Sn2P3O10 crystallizes in the monoclinic P2_1/m space group. Sn(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(5) atom to form SnO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  an edgeedge with one Sn(1)O5 square pyramid. The Sn(1)-O(1) bond length is 2.21 Å. The Sn(1)-O(2) bond length is 2.53 Å. The Sn(1)-O(3) bond length is 2.17 Å. The Sn(1)-O(4) bond length is 2.48 Å. The Sn(1)-O(5) bond length is 2.13 Å. There are three inequivalent P sites. In the first P site, P(1) is bonded to one O(6), one O(7), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Sn(1)O5 square pyramids,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one P(3)O4 tetrahedra. The P(1)-O(6) bond length is 1.59 Å. The P(1)-O(7) bond length is 1.59 Å. Both P(1)-O(1) bond lengths are 1.51 Å. In the second P site, P(2) is bonded to one O(4), one O(7), and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Sn(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. The P(2)-O(4) bond length is 1.55 Å. The P(2)-O(7) bond length is 1.62 Å. Both P(2)-O(3) bond lengths are 1.52 Å. In the third P site, P(3) is bonded to one O(2), one O(6), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with four equivalent Sn(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. The P(3)-O(2) bond length is 1.55 Å. The P(3)-O(6) bond length is 1.62 Å. Both P(3)-O(5) bond lengths are 1.53 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Sn(1) and one P(3) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sn(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Sn(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(3) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.