SnP2O9 crystallizes in the monoclinic C2/c space group. Sn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form SnO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. 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. The corner-sharing octahedral tilt angles range from 33-45°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 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 bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one P(1) and one O(5) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent O(4) atoms.
SnP2O9 crystallizes in the monoclinic C2/c space group. Sn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form SnO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. Both Sn(1)-O(1) bond lengths are 2.06 Å. Both Sn(1)-O(2) bond lengths are 2.07 Å. Both Sn(1)-O(3) bond lengths are 2.06 Å. 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. The corner-sharing octahedral tilt angles range from 33-45°. The P(1)-O(1) bond length is 1.52 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.55 Å. The P(1)-O(4) bond length is 1.59 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 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 bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one P(1) and one O(5) atom. The O(4)-O(5) bond length is 2.09 Å. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent O(4) atoms.