CoAsSe is Spinel-like structured and crystallizes in the orthorhombic Pbca space group. Co(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form CoAs3Se3 octahedra that share corners with ten equivalent Co(1)As3Se3 octahedra, corners with three equivalent As(1)Co3Se tetrahedra, corners with three equivalent Se(1)Co3As tetrahedra, and  an edgeedge with one Co(1)As3Se3 octahedra. The corner-sharing octahedral tilt angles range from 54-66°. As(1) is bonded to three equivalent Co(1) and one Se(1) atom to form AsCo3Se tetrahedra that share corners with three equivalent Co(1)As3Se3 octahedra, corners with four equivalent As(1)Co3Se tetrahedra, corners with nine equivalent Se(1)Co3As tetrahedra, and  an edgeedge with one As(1)Co3Se tetrahedra. The corner-sharing octahedral tilt angles range from 76-81°. Se(1) is bonded to three equivalent Co(1) and one As(1) atom to form SeCo3As tetrahedra that share corners with three equivalent Co(1)As3Se3 octahedra, corners with six equivalent Se(1)Co3As tetrahedra, and corners with nine equivalent As(1)Co3Se tetrahedra. The corner-sharing octahedral tilt angles range from 71-81°.
CoAsSe is Spinel-like structured and crystallizes in the orthorhombic Pbca space group. Co(1) is bonded to three equivalent As(1) and three equivalent Se(1) atoms to form CoAs3Se3 octahedra that share corners with ten equivalent Co(1)As3Se3 octahedra, corners with three equivalent As(1)Co3Se tetrahedra, corners with three equivalent Se(1)Co3As tetrahedra, and  an edgeedge with one Co(1)As3Se3 octahedra. The corner-sharing octahedral tilt angles range from 54-66°. There are two shorter (2.33 Å) and one longer (2.35 Å) Co(1)-As(1) bond length. There is one shorter (2.37 Å) and two longer (2.42 Å) Co(1)-Se(1) bond lengths. As(1) is bonded to three equivalent Co(1) and one Se(1) atom to form AsCo3Se tetrahedra that share corners with three equivalent Co(1)As3Se3 octahedra, corners with four equivalent As(1)Co3Se tetrahedra, corners with nine equivalent Se(1)Co3As tetrahedra, and  an edgeedge with one As(1)Co3Se tetrahedra. The corner-sharing octahedral tilt angles range from 76-81°. The As(1)-Se(1) bond length is 2.45 Å. Se(1) is bonded to three equivalent Co(1) and one As(1) atom to form SeCo3As tetrahedra that share corners with three equivalent Co(1)As3Se3 octahedra, corners with six equivalent Se(1)Co3As tetrahedra, and corners with nine equivalent As(1)Co3Se tetrahedra. The corner-sharing octahedral tilt angles range from 71-81°.