CuSeO3 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form distorted edge-sharing CuO6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(5), and one O(6) atom. In the second Se site, Se(2) is bonded in a distorted trigonal non-coplanar geometry to one O(2), one O(3), and one O(4) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Cu(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Se(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Cu(2) and one Se(1) atom.
CuSeO3 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Cu(1)-O(1) bond length is 1.96 Å. The Cu(1)-O(2) bond length is 2.43 Å. The Cu(1)-O(3) bond length is 1.94 Å. The Cu(1)-O(4) bond length is 1.97 Å. The Cu(1)-O(5) bond length is 1.98 Å. In the second Cu site, Cu(2) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms to form distorted edge-sharing CuO6 octahedra. The Cu(2)-O(2) bond length is 2.01 Å. The Cu(2)-O(3) bond length is 2.41 Å. The Cu(2)-O(4) bond length is 1.94 Å. The Cu(2)-O(5) bond length is 2.43 Å. There is one shorter (1.94 Å) and one longer (1.97 Å) Cu(2)-O(6) bond length. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(5), and one O(6) atom. The Se(1)-O(1) bond length is 1.69 Å. The Se(1)-O(5) bond length is 1.71 Å. The Se(1)-O(6) bond length is 1.74 Å. In the second Se site, Se(2) is bonded in a distorted trigonal non-coplanar geometry to one O(2), one O(3), and one O(4) atom. The Se(2)-O(2) bond length is 1.71 Å. The Se(2)-O(3) bond length is 1.71 Å. The Se(2)-O(4) bond length is 1.75 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Cu(1) and one Se(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Se(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Cu(2) and one Se(1) atom.