CuH10SeO9 crystallizes in the triclinic P-1 space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form CuO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra. In the second Cu site, Cu(2) is bonded to two equivalent O(3), two equivalent O(8), and two equivalent O(9) atoms to form CuO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra. There are ten inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(3) and one O(4) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(3) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(6) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(2) and one O(5) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(6) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(7) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(7) atom. In the ninth H site, H(9) is bonded in a distorted single-bond geometry to one O(1) and one O(9) atom. In the tenth H site, H(10) is bonded in a distorted single-bond geometry to one O(4) and one O(9) atom. Se(1) is bonded to one O(1), one O(2), one O(4), and one O(8) atom to form SeO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one Cu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one H(9) and one Se(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cu(1), one H(4), and one Se(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(2), one H(1), and one H(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one H(1), one H(10), and one Se(1) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one H(4) and one H(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one H(3), and one H(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one H(7), and one H(8) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Cu(2) and one Se(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Cu(2), one H(10), and one H(9) atom.
CuH10SeO9 crystallizes in the triclinic P-1 space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form CuO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra. Both Cu(1)-O(2) bond lengths are 2.38 Å. Both Cu(1)-O(6) bond lengths are 2.01 Å. Both Cu(1)-O(7) bond lengths are 1.97 Å. In the second Cu site, Cu(2) is bonded to two equivalent O(3), two equivalent O(8), and two equivalent O(9) atoms to form CuO6 octahedra that share corners with two equivalent Se(1)O4 tetrahedra. Both Cu(2)-O(3) bond lengths are 1.98 Å. Both Cu(2)-O(8) bond lengths are 2.48 Å. Both Cu(2)-O(9) bond lengths are 1.94 Å. There are ten inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(3) and one O(4) atom. The H(1)-O(3) bond length is 1.00 Å. The H(1)-O(4) bond length is 1.66 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(3) atom. The H(2)-O(3) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(6) atom. The H(3)-O(6) bond length is 1.00 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(2) and one O(5) atom. The H(4)-O(2) bond length is 1.73 Å. The H(4)-O(5) bond length is 1.00 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. The H(5)-O(5) bond length is 0.98 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(6) atom. The H(6)-O(6) bond length is 0.99 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(7) atom. The H(7)-O(7) bond length is 1.00 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(7) atom. The H(8)-O(7) bond length is 0.99 Å. In the ninth H site, H(9) is bonded in a distorted single-bond geometry to one O(1) and one O(9) atom. The H(9)-O(1) bond length is 1.66 Å. The H(9)-O(9) bond length is 1.00 Å. In the tenth H site, H(10) is bonded in a distorted single-bond geometry to one O(4) and one O(9) atom. The H(10)-O(4) bond length is 1.67 Å. The H(10)-O(9) bond length is 1.00 Å. Se(1) is bonded to one O(1), one O(2), one O(4), and one O(8) atom to form SeO4 tetrahedra that share  a cornercorner with one Cu(1)O6 octahedra and  a cornercorner with one Cu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. The Se(1)-O(1) bond length is 1.70 Å. The Se(1)-O(2) bond length is 1.67 Å. The Se(1)-O(4) bond length is 1.68 Å. The Se(1)-O(8) bond length is 1.68 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one H(9) and one Se(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Cu(1), one H(4), and one Se(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(2), one H(1), and one H(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one H(1), one H(10), and one Se(1) atom. In the fifth O site, O(5) is bonded in a water-like geometry to one H(4) and one H(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one H(3), and one H(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one H(7), and one H(8) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Cu(2) and one Se(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Cu(2), one H(10), and one H(9) atom.