K2SeS3O7 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 9-coordinate geometry to one O(1), one O(2), one O(3), one O(6), one O(7), two equivalent O(4), and two equivalent O(5) atoms. In the second K site, K(2) is bonded to one O(5), one O(7), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing KO8 hexagonal bipyramids. Se(1) is bonded in a water-like geometry to one S(1) and one S(2) atom. There are three inequivalent S sites. In the first S site, S(1) is bonded in a water-like geometry to one Se(1) and one S(3) atom. In the second S site, S(2) is bonded in a trigonal non-coplanar geometry to one Se(1), one O(1), one O(2), and one O(3) atom. In the third S site, S(3) is bonded in a trigonal non-coplanar geometry to one S(1), one O(4), one O(5), and one O(6) atom. There are seven inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(2) atom. In the second O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one S(3) atom. In the third O site, O(5) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one S(3) atom. In the fourth O site, O(6) is bonded in a distorted water-like geometry to one K(1) and one S(3) atom. In the fifth O site, O(7) is bonded in a bent 120 degrees geometry to one K(1) and one K(2) atom. In the sixth O site, O(1) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(2) atom. In the seventh O site, O(2) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(2) atom.
K2SeS3O7 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 9-coordinate geometry to one O(1), one O(2), one O(3), one O(6), one O(7), two equivalent O(4), and two equivalent O(5) atoms. The K(1)-O(1) bond length is 3.23 Å. The K(1)-O(2) bond length is 2.85 Å. The K(1)-O(3) bond length is 3.16 Å. The K(1)-O(6) bond length is 2.81 Å. The K(1)-O(7) bond length is 2.92 Å. There is one shorter (2.80 Å) and one longer (3.10 Å) K(1)-O(4) bond length. There is one shorter (2.97 Å) and one longer (3.09 Å) K(1)-O(5) bond length. In the second K site, K(2) is bonded to one O(5), one O(7), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing KO8 hexagonal bipyramids. The K(2)-O(5) bond length is 2.72 Å. The K(2)-O(7) bond length is 2.81 Å. There is one shorter (2.83 Å) and one longer (2.89 Å) K(2)-O(1) bond length. Both K(2)-O(2) bond lengths are 3.04 Å. There is one shorter (2.77 Å) and one longer (3.16 Å) K(2)-O(3) bond length. Se(1) is bonded in a water-like geometry to one S(1) and one S(2) atom. The Se(1)-S(1) bond length is 2.17 Å. The Se(1)-S(2) bond length is 2.37 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded in a water-like geometry to one Se(1) and one S(3) atom. The S(1)-S(3) bond length is 2.22 Å. In the second S site, S(2) is bonded in a trigonal non-coplanar geometry to one Se(1), one O(1), one O(2), and one O(3) atom. The S(2)-O(1) bond length is 1.47 Å. The S(2)-O(2) bond length is 1.47 Å. The S(2)-O(3) bond length is 1.47 Å. In the third S site, S(3) is bonded in a trigonal non-coplanar geometry to one S(1), one O(4), one O(5), and one O(6) atom. The S(3)-O(4) bond length is 1.46 Å. The S(3)-O(5) bond length is 1.48 Å. The S(3)-O(6) bond length is 1.46 Å. There are seven inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(2) atom. In the second O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one S(3) atom. In the third O site, O(5) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one S(3) atom. In the fourth O site, O(6) is bonded in a distorted water-like geometry to one K(1) and one S(3) atom. In the fifth O site, O(7) is bonded in a bent 120 degrees geometry to one K(1) and one K(2) atom. In the sixth O site, O(1) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(2) atom. In the seventh O site, O(2) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(2) atom.