Cu2OSeO3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to two equivalent O(3) and two equivalent O(4) atoms. Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(2), and one Se(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Cu(1) and one Se(1) atom. In the third O site, O(3) is bonded to one Cu(2), one Cu(3), and two equivalent Cu(1) atoms to form corner-sharing OCu4 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(3), and one Se(1) atom.
Cu2OSeO3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. The Cu(1)-O(1) bond length is 2.47 Å. The Cu(1)-O(4) bond length is 2.43 Å. There is one shorter (1.96 Å) and one longer (2.01 Å) Cu(1)-O(2) bond length. There is one shorter (1.95 Å) and one longer (1.98 Å) Cu(1)-O(3) bond length. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. Both Cu(2)-O(1) bond lengths are 1.93 Å. Both Cu(2)-O(3) bond lengths are 1.96 Å. In the third Cu site, Cu(3) is bonded in a square co-planar geometry to two equivalent O(3) and two equivalent O(4) atoms. Both Cu(3)-O(3) bond lengths are 1.93 Å. Both Cu(3)-O(4) bond lengths are 1.95 Å. Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(4) atom. The Se(1)-O(1) bond length is 1.70 Å. The Se(1)-O(2) bond length is 1.74 Å. The Se(1)-O(4) bond length is 1.71 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(2), and one Se(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Cu(1) and one Se(1) atom. In the third O site, O(3) is bonded to one Cu(2), one Cu(3), and two equivalent Cu(1) atoms to form corner-sharing OCu4 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Cu(1), one Cu(3), and one Se(1) atom.