CuSe2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. Cu(1) is bonded to six equivalent Se(1) atoms to form CuSe6 octahedra that share corners with eight equivalent Cu(1)Se6 octahedra, corners with six equivalent Se(1)Cu3Se tetrahedra, and edges with two equivalent Cu(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 61°. Se(1) is bonded to three equivalent Cu(1) and one Se(1) atom to form distorted SeCu3Se tetrahedra that share corners with three equivalent Cu(1)Se6 octahedra, corners with thirteen equivalent Se(1)Cu3Se tetrahedra, and  an edgeedge with one Se(1)Cu3Se tetrahedra. The corner-sharing octahedral tilt angles range from 71-74°.
CuSe2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. Cu(1) is bonded to six equivalent Se(1) atoms to form CuSe6 octahedra that share corners with eight equivalent Cu(1)Se6 octahedra, corners with six equivalent Se(1)Cu3Se tetrahedra, and edges with two equivalent Cu(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 61°. All Cu(1)-Se(1) bond lengths are 2.56 Å. Se(1) is bonded to three equivalent Cu(1) and one Se(1) atom to form distorted SeCu3Se tetrahedra that share corners with three equivalent Cu(1)Se6 octahedra, corners with thirteen equivalent Se(1)Cu3Se tetrahedra, and  an edgeedge with one Se(1)Cu3Se tetrahedra. The corner-sharing octahedral tilt angles range from 71-74°. The Se(1)-Se(1) bond length is 2.34 Å.