K2SnP2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. Sn(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(6), 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(3), one O(5), and one O(7) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a distorted single-bond geometry to two equivalent K(2), one Sn(1), and one P(1) atom. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one K(2), one Sn(1), and one P(1) atom. In the third O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1), one Sn(1), and one P(2) atom. In the fourth O site, O(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one P(1) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one P(2) atom. In the sixth O site, O(5) is bonded in a 2-coordinate geometry to one K(1), one P(1), and one P(2) atom. In the seventh O site, O(6) is bonded in a 1-coordinate geometry to two equivalent K(2), one Sn(1), and one P(2) atom.
K2SnP2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. The K(1)-O(3) bond length is 2.81 Å. The K(1)-O(5) bond length is 2.90 Å. There is one shorter (2.73 Å) and one longer (3.04 Å) K(1)-O(2) bond length. There is one shorter (2.68 Å) and one longer (2.73 Å) K(1)-O(4) bond length. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. The K(2)-O(1) bond length is 2.82 Å. The K(2)-O(4) bond length is 3.34 Å. There is one shorter (2.77 Å) and one longer (3.17 Å) K(2)-O(3) bond length. There is one shorter (2.89 Å) and one longer (3.31 Å) K(2)-O(6) bond length. There is one shorter (2.84 Å) and one longer (2.93 Å) K(2)-O(7) bond length. Sn(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(6), and one O(7) atom. The Sn(1)-O(1) bond length is 2.17 Å. The Sn(1)-O(2) bond length is 2.42 Å. The Sn(1)-O(6) bond length is 2.19 Å. The Sn(1)-O(7) bond length is 2.42 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form corner-sharing PO4 tetrahedra. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(3) bond length is 1.51 Å. The P(1)-O(5) bond length is 1.65 Å. The P(1)-O(7) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. The P(2)-O(2) bond length is 1.54 Å. The P(2)-O(4) bond length is 1.51 Å. The P(2)-O(5) bond length is 1.65 Å. The P(2)-O(6) bond length is 1.56 Å. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a distorted single-bond geometry to two equivalent K(2), one Sn(1), and one P(1) atom. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one K(2), one Sn(1), and one P(1) atom. In the third O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1), one Sn(1), and one P(2) atom. In the fourth O site, O(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one P(1) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one P(2) atom. In the sixth O site, O(5) is bonded in a 2-coordinate geometry to one K(1), one P(1), and one P(2) atom. In the seventh O site, O(6) is bonded in a 1-coordinate geometry to two equivalent K(2), one Sn(1), and one P(2) atom.