K2CaH2S2O9 crystallizes in the monoclinic P2_1/m space group. K(1) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(6), one O(7), two equivalent O(4), and two equivalent O(5) atoms. Ca(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(7), two equivalent O(6), and four equivalent O(2) atoms. H(1) is bonded in a single-bond geometry to one O(1) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(6) atoms. In the second S site, S(2) is bonded in a tetrahedral geometry to one O(3), one O(7), and two equivalent O(2) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to two equivalent K(1), one Ca(1), and two equivalent H(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one S(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1), one Ca(1), and one S(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to four equivalent K(1) and one S(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to four equivalent K(1) and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one K(1), one Ca(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted tetrahedral geometry to two equivalent K(1), one Ca(1), and one S(2) atom.
K2CaH2S2O9 crystallizes in the monoclinic P2_1/m space group. K(1) is bonded in a 8-coordinate geometry to one O(1), 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 3.04 Å. The K(1)-O(3) bond length is 2.78 Å. The K(1)-O(6) bond length is 3.00 Å. The K(1)-O(7) bond length is 2.73 Å. There is one shorter (2.88 Å) and one longer (2.94 Å) K(1)-O(4) bond length. There is one shorter (2.88 Å) and one longer (3.12 Å) K(1)-O(5) bond length. Ca(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(7), two equivalent O(6), and four equivalent O(2) atoms. The Ca(1)-O(1) bond length is 2.49 Å. The Ca(1)-O(3) bond length is 2.80 Å. The Ca(1)-O(7) bond length is 2.43 Å. Both Ca(1)-O(6) bond lengths are 2.58 Å. There are two shorter (2.48 Å) and two longer (2.55 Å) Ca(1)-O(2) bond lengths. H(1) is bonded in a single-bond geometry to one O(1) atom. The H(1)-O(1) bond length is 0.99 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(6) atoms. The S(1)-O(4) bond length is 1.49 Å. The S(1)-O(5) bond length is 1.49 Å. Both S(1)-O(6) bond lengths are 1.50 Å. In the second S site, S(2) is bonded in a tetrahedral geometry to one O(3), one O(7), and two equivalent O(2) atoms. The S(2)-O(3) bond length is 1.48 Å. The S(2)-O(7) bond length is 1.50 Å. Both S(2)-O(2) bond lengths are 1.50 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to two equivalent K(1), one Ca(1), and two equivalent H(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one S(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1), one Ca(1), and one S(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to four equivalent K(1) and one S(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to four equivalent K(1) and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one K(1), one Ca(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted tetrahedral geometry to two equivalent K(1), one Ca(1), and one S(2) atom.