KCaNi2H3(SeO5)2 crystallizes in the triclinic P1 space group. K(1) is bonded in a 7-coordinate geometry to one Se(1), one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. Ca(1) is bonded in a distorted rectangular see-saw-like geometry to one O(10), one O(3), one O(4), and one O(9) atom. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(10), one O(6), one O(7), one O(8), and one O(9) atom to form distorted NiO5 trigonal bipyramids that share corners with two equivalent Se(2)O4 tetrahedra. In the second Ni site, Ni(2) is bonded in a 5-coordinate geometry to one O(10), one O(5), one O(7), one O(8), and one O(9) atom. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. In the second H site, H(2) is bonded in a distorted linear geometry to one O(3) and one O(8) atom. In the third H site, H(3) is bonded in a distorted single-bond geometry to one O(8) atom. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted trigonal non-coplanar geometry to one K(1), one O(1), one O(3), and one O(4) atom. In the second Se site, Se(2) is bonded to one O(10), one O(2), one O(5), and one O(6) atom to form SeO4 tetrahedra that share corners with two equivalent Ni(1)O5 trigonal bipyramids. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one K(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1) and one Se(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Ca(1), one H(2), and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one K(1), one Ca(1), and one Se(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one K(1), one Ni(2), and one Se(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one K(1), one Ni(1), and one Se(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Ni(1), one Ni(2), and one H(1) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Ni(1), one Ni(2), one H(2), and one H(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Ni(1), and one Ni(2) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ca(1), one Ni(1), one Ni(2), and one Se(2) atom.
KCaNi2H3(SeO5)2 crystallizes in the triclinic P1 space group. K(1) is bonded in a 7-coordinate geometry to one Se(1), one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The K(1)-Se(1) bond length is 3.37 Å. The K(1)-O(1) bond length is 2.74 Å. The K(1)-O(2) bond length is 2.67 Å. The K(1)-O(3) bond length is 2.87 Å. The K(1)-O(4) bond length is 2.60 Å. The K(1)-O(5) bond length is 3.14 Å. The K(1)-O(6) bond length is 2.75 Å. Ca(1) is bonded in a distorted rectangular see-saw-like geometry to one O(10), one O(3), one O(4), and one O(9) atom. The Ca(1)-O(10) bond length is 2.56 Å. The Ca(1)-O(3) bond length is 2.34 Å. The Ca(1)-O(4) bond length is 2.21 Å. The Ca(1)-O(9) bond length is 2.12 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(10), one O(6), one O(7), one O(8), and one O(9) atom to form distorted NiO5 trigonal bipyramids that share corners with two equivalent Se(2)O4 tetrahedra. The Ni(1)-O(10) bond length is 2.17 Å. The Ni(1)-O(6) bond length is 2.02 Å. The Ni(1)-O(7) bond length is 2.00 Å. The Ni(1)-O(8) bond length is 2.16 Å. The Ni(1)-O(9) bond length is 1.95 Å. In the second Ni site, Ni(2) is bonded in a 5-coordinate geometry to one O(10), one O(5), one O(7), one O(8), and one O(9) atom. The Ni(2)-O(10) bond length is 2.22 Å. The Ni(2)-O(5) bond length is 2.02 Å. The Ni(2)-O(7) bond length is 2.04 Å. The Ni(2)-O(8) bond length is 2.18 Å. The Ni(2)-O(9) bond length is 1.90 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(7) atom. The H(1)-O(7) bond length is 0.98 Å. In the second H site, H(2) is bonded in a distorted linear geometry to one O(3) and one O(8) atom. The H(2)-O(3) bond length is 1.49 Å. The H(2)-O(8) bond length is 1.06 Å. In the third H site, H(3) is bonded in a distorted single-bond geometry to one O(8) atom. The H(3)-O(8) bond length is 1.03 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted trigonal non-coplanar geometry to one K(1), one O(1), one O(3), and one O(4) atom. The Se(1)-O(1) bond length is 1.67 Å. The Se(1)-O(3) bond length is 1.81 Å. The Se(1)-O(4) bond length is 1.74 Å. In the second Se site, Se(2) is bonded to one O(10), one O(2), one O(5), and one O(6) atom to form SeO4 tetrahedra that share corners with two equivalent Ni(1)O5 trigonal bipyramids. The Se(2)-O(10) bond length is 1.78 Å. The Se(2)-O(2) bond length is 1.63 Å. The Se(2)-O(5) bond length is 1.68 Å. The Se(2)-O(6) bond length is 1.68 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one K(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one K(1) and one Se(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Ca(1), one H(2), and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one K(1), one Ca(1), and one Se(1) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one K(1), one Ni(2), and one Se(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one K(1), one Ni(1), and one Se(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Ni(1), one Ni(2), and one H(1) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Ni(1), one Ni(2), one H(2), and one H(3) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Ni(1), and one Ni(2) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ca(1), one Ni(1), one Ni(2), and one Se(2) atom.