Na2CdH4(SeO5)2 crystallizes in the monoclinic P2_1/c space group. Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. Cd(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form CdO6 octahedra that share corners with four equivalent Se(1)O4 tetrahedra. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) and one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) and one O(5) atom. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SeO4 tetrahedra that share corners with two equivalent Cd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted water-like geometry to one Na(1), one Cd(1), one H(1), and one H(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one H(1), and one Se(1) atom. In the third O site, O(2) is bonded to two equivalent Na(1), one Cd(1), and one Se(1) atom to form a mixture of distorted corner and edge-sharing ONa2CdSe tetrahedra. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one Cd(1), and one Se(1) atom. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(1), one H(2), and one Se(1) atom.
Na2CdH4(SeO5)2 crystallizes in the monoclinic P2_1/c space group. Na(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. The Na(1)-O(1) bond length is 2.61 Å. The Na(1)-O(3) bond length is 2.52 Å. The Na(1)-O(5) bond length is 2.42 Å. There is one shorter (2.63 Å) and one longer (2.75 Å) Na(1)-O(2) bond length. There is one shorter (2.62 Å) and one longer (2.64 Å) Na(1)-O(4) bond length. Cd(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form CdO6 octahedra that share corners with four equivalent Se(1)O4 tetrahedra. Both Cd(1)-O(2) bond lengths are 2.39 Å. Both Cd(1)-O(3) bond lengths are 2.31 Å. Both Cd(1)-O(5) bond lengths are 2.31 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) and one O(5) atom. The H(1)-O(1) bond length is 1.69 Å. The H(1)-O(5) bond length is 1.00 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) and one O(5) atom. The H(2)-O(4) bond length is 1.76 Å. The H(2)-O(5) bond length is 1.00 Å. Se(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SeO4 tetrahedra that share corners with two equivalent Cd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. The Se(1)-O(1) bond length is 1.66 Å. The Se(1)-O(2) bond length is 1.69 Å. The Se(1)-O(3) bond length is 1.69 Å. The Se(1)-O(4) bond length is 1.67 Å. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted water-like geometry to one Na(1), one Cd(1), one H(1), and one H(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one H(1), and one Se(1) atom. In the third O site, O(2) is bonded to two equivalent Na(1), one Cd(1), and one Se(1) atom to form a mixture of distorted corner and edge-sharing ONa2CdSe tetrahedra. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one Cd(1), and one Se(1) atom. In the fifth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(1), one H(2), and one Se(1) atom.