K2SeS2O6 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 7-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(2), and two equivalent O(3) atoms. In the second K site, K(2) is bonded in a distorted pentagonal pyramidal geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. Se(1) is bonded in a distorted water-like geometry to one S(1) and one S(2) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded in a trigonal non-coplanar geometry to one Se(1), one O(4), one O(5), and one O(6) 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. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(2) and one S(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one S(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one S(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one S(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one K(1), one K(2), and one S(1) atom.
K2SeS2O6 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 7-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(2), and two equivalent O(3) atoms. The K(1)-O(4) bond length is 2.86 Å. The K(1)-O(5) bond length is 3.03 Å. The K(1)-O(6) bond length is 2.71 Å. There is one shorter (2.94 Å) and one longer (3.03 Å) K(1)-O(2) bond length. There is one shorter (2.84 Å) and one longer (2.85 Å) K(1)-O(3) bond length. In the second K site, K(2) is bonded in a distorted pentagonal pyramidal geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The K(2)-O(1) bond length is 2.72 Å. The K(2)-O(2) bond length is 2.87 Å. The K(2)-O(3) bond length is 2.82 Å. The K(2)-O(4) bond length is 2.88 Å. The K(2)-O(5) bond length is 2.83 Å. The K(2)-O(6) bond length is 2.74 Å. Se(1) is bonded in a distorted water-like geometry to one S(1) and one S(2) atom. The Se(1)-S(1) bond length is 2.31 Å. The Se(1)-S(2) bond length is 2.31 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a trigonal non-coplanar geometry to one Se(1), one O(4), one O(5), and one O(6) atom. The S(1)-O(4) bond length is 1.47 Å. The S(1)-O(5) bond length is 1.47 Å. The S(1)-O(6) bond length is 1.47 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 1.46 Å. The S(2)-O(2) bond length is 1.47 Å. The S(2)-O(3) bond length is 1.48 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(2) and one S(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one S(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one S(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one S(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one K(1), one K(2), and one S(1) atom.