CuSeO4 crystallizes in the orthorhombic Cmcm space group. Cu(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CuO6 octahedra that share corners with six equivalent Se(1)O4 tetrahedra and edges with two equivalent Cu(1)O6 octahedra. Se(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SeO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. There are two 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 planar geometry to two equivalent Cu(1) and one Se(1) atom.
CuSeO4 crystallizes in the orthorhombic Cmcm space group. Cu(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CuO6 octahedra that share corners with six equivalent Se(1)O4 tetrahedra and edges with two equivalent Cu(1)O6 octahedra. Both Cu(1)-O(1) bond lengths are 1.90 Å. All Cu(1)-O(2) bond lengths are 2.18 Å. Se(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SeO4 tetrahedra that share corners with six equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. Both Se(1)-O(1) bond lengths are 1.65 Å. Both Se(1)-O(2) bond lengths are 1.67 Å. There are two 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 planar geometry to two equivalent Cu(1) and one Se(1) atom.