NaCu2H2(SeO5)2 crystallizes in the monoclinic C2/m space group. Na(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms to form distorted NaO8 hexagonal bipyramids that share corners with four equivalent Se(1)O4 tetrahedra, edges with four equivalent Cu(1)O6 octahedra, and edges with two equivalent Se(1)O4 tetrahedra. Cu(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CuO6 octahedra that share corners with four equivalent Se(1)O4 tetrahedra, edges with two equivalent Na(1)O8 hexagonal bipyramids, and edges with two equivalent Cu(1)O6 octahedra. H(1) is bonded in a single-bond geometry to one O(4) atom. Se(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SeO4 tetrahedra that share corners with two equivalent Na(1)O8 hexagonal bipyramids, corners with four equivalent Cu(1)O6 octahedra, and  an edgeedge with one Na(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 43-58°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), two equivalent Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Na(1) and one Se(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Na(1), one Cu(1), and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cu(1) and one H(1) atom.
NaCu2H2(SeO5)2 crystallizes in the monoclinic C2/m space group. Na(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms to form distorted NaO8 hexagonal bipyramids that share corners with four equivalent Se(1)O4 tetrahedra, edges with four equivalent Cu(1)O6 octahedra, and edges with two equivalent Se(1)O4 tetrahedra. Both Na(1)-O(1) bond lengths are 2.77 Å. Both Na(1)-O(2) bond lengths are 2.73 Å. All Na(1)-O(3) bond lengths are 2.56 Å. Cu(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CuO6 octahedra that share corners with four equivalent Se(1)O4 tetrahedra, edges with two equivalent Na(1)O8 hexagonal bipyramids, and edges with two equivalent Cu(1)O6 octahedra. Both Cu(1)-O(1) bond lengths are 2.40 Å. Both Cu(1)-O(3) bond lengths are 1.97 Å. Both Cu(1)-O(4) bond lengths are 1.90 Å. H(1) is bonded in a single-bond geometry to one O(4) atom. The H(1)-O(4) bond length is 1.00 Å. Se(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SeO4 tetrahedra that share corners with two equivalent Na(1)O8 hexagonal bipyramids, corners with four equivalent Cu(1)O6 octahedra, and  an edgeedge with one Na(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 43-58°. The Se(1)-O(1) bond length is 1.67 Å. The Se(1)-O(2) bond length is 1.65 Å. Both Se(1)-O(3) bond lengths are 1.72 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), two equivalent Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Na(1) and one Se(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Na(1), one Cu(1), and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cu(1) and one H(1) atom.