Cr6Co2CuSe12 crystallizes in the monoclinic C2/m space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(6), two equivalent Se(2), and two equivalent Se(4) atoms to form distorted CrSe6 octahedra that share corners with two equivalent Cu(1)Se6 octahedra, corners with four equivalent Co(1)Se6 octahedra, edges with two equivalent Cr(1)Se6 octahedra, edges with two equivalent Cr(2)Se6 octahedra, edges with two equivalent Cr(3)Se6 octahedra, and  a faceface with one Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 49-52°. In the second Cr site, Cr(2) is bonded to one Se(2), two equivalent Se(1), and three equivalent Se(5) atoms to form CrSe6 octahedra that share corners with six equivalent Co(1)Se6 octahedra, edges with two equivalent Cr(1)Se6 octahedra, edges with four equivalent Cr(2)Se6 octahedra, and  a faceface with one Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. In the third Cr site, Cr(3) is bonded to one Se(4), two equivalent Se(6), and three equivalent Se(3) atoms to form distorted CrSe6 octahedra that share corners with two equivalent Co(1)Se6 octahedra, corners with four equivalent Cu(1)Se6 octahedra, edges with two equivalent Cr(1)Se6 octahedra, edges with four equivalent Cr(3)Se6 octahedra, and  a faceface with one Cu(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. Co(1) is bonded to one Se(5), one Se(6), two equivalent Se(1), and two equivalent Se(2) atoms to form CoSe6 octahedra that share corners with two equivalent Cr(3)Se6 octahedra, corners with four equivalent Cr(1)Se6 octahedra, corners with six equivalent Cr(2)Se6 octahedra, edges with two equivalent Co(1)Se6 octahedra,  a faceface with one Cr(1)Se6 octahedra, and  a faceface with one Cr(2)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. Cu(1) is bonded to two equivalent Se(4) and four equivalent Se(3) atoms to form CuSe6 octahedra that share corners with four equivalent Cr(1)Se6 octahedra, corners with eight equivalent Cr(3)Se6 octahedra, edges with two equivalent Cu(1)Se6 octahedra, and faces with two equivalent Cr(3)Se6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cr(1), two equivalent Cr(2), and two equivalent Co(1) atoms to form a mixture of distorted corner and edge-sharing SeCr3Co2 square pyramids. In the second Se site, Se(2) is bonded to one Cr(2), two equivalent Cr(1), and two equivalent Co(1) atoms to form a mixture of distorted corner and edge-sharing SeCr3Co2 square pyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to three equivalent Cr(3) and two equivalent Cu(1) atoms. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Cr(3), two equivalent Cr(1), and one Cu(1) atom. In the fifth Se site, Se(5) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(2) and one Co(1) atom. In the sixth Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(3), and one Co(1) atom.
Cr6Co2CuSe12 crystallizes in the monoclinic C2/m space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one Se(1), one Se(6), two equivalent Se(2), and two equivalent Se(4) atoms to form distorted CrSe6 octahedra that share corners with two equivalent Cu(1)Se6 octahedra, corners with four equivalent Co(1)Se6 octahedra, edges with two equivalent Cr(1)Se6 octahedra, edges with two equivalent Cr(2)Se6 octahedra, edges with two equivalent Cr(3)Se6 octahedra, and  a faceface with one Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 49-52°. The Cr(1)-Se(1) bond length is 2.62 Å. The Cr(1)-Se(6) bond length is 2.49 Å. Both Cr(1)-Se(2) bond lengths are 2.62 Å. Both Cr(1)-Se(4) bond lengths are 2.48 Å. In the second Cr site, Cr(2) is bonded to one Se(2), two equivalent Se(1), and three equivalent Se(5) atoms to form CrSe6 octahedra that share corners with six equivalent Co(1)Se6 octahedra, edges with two equivalent Cr(1)Se6 octahedra, edges with four equivalent Cr(2)Se6 octahedra, and  a faceface with one Co(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. The Cr(2)-Se(2) bond length is 2.61 Å. Both Cr(2)-Se(1) bond lengths are 2.62 Å. There are two shorter (2.50 Å) and one longer (2.51 Å) Cr(2)-Se(5) bond length. In the third Cr site, Cr(3) is bonded to one Se(4), two equivalent Se(6), and three equivalent Se(3) atoms to form distorted CrSe6 octahedra that share corners with two equivalent Co(1)Se6 octahedra, corners with four equivalent Cu(1)Se6 octahedra, edges with two equivalent Cr(1)Se6 octahedra, edges with four equivalent Cr(3)Se6 octahedra, and  a faceface with one Cu(1)Se6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. The Cr(3)-Se(4) bond length is 2.53 Å. Both Cr(3)-Se(6) bond lengths are 2.51 Å. There is one shorter (2.54 Å) and two longer (2.56 Å) Cr(3)-Se(3) bond lengths. Co(1) is bonded to one Se(5), one Se(6), two equivalent Se(1), and two equivalent Se(2) atoms to form CoSe6 octahedra that share corners with two equivalent Cr(3)Se6 octahedra, corners with four equivalent Cr(1)Se6 octahedra, corners with six equivalent Cr(2)Se6 octahedra, edges with two equivalent Co(1)Se6 octahedra,  a faceface with one Cr(1)Se6 octahedra, and  a faceface with one Cr(2)Se6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. The Co(1)-Se(5) bond length is 2.47 Å. The Co(1)-Se(6) bond length is 2.48 Å. Both Co(1)-Se(1) bond lengths are 2.52 Å. Both Co(1)-Se(2) bond lengths are 2.51 Å. Cu(1) is bonded to two equivalent Se(4) and four equivalent Se(3) atoms to form CuSe6 octahedra that share corners with four equivalent Cr(1)Se6 octahedra, corners with eight equivalent Cr(3)Se6 octahedra, edges with two equivalent Cu(1)Se6 octahedra, and faces with two equivalent Cr(3)Se6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. Both Cu(1)-Se(4) bond lengths are 2.54 Å. All Cu(1)-Se(3) bond lengths are 2.59 Å. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cr(1), two equivalent Cr(2), and two equivalent Co(1) atoms to form a mixture of distorted corner and edge-sharing SeCr3Co2 square pyramids. In the second Se site, Se(2) is bonded to one Cr(2), two equivalent Cr(1), and two equivalent Co(1) atoms to form a mixture of distorted corner and edge-sharing SeCr3Co2 square pyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to three equivalent Cr(3) and two equivalent Cu(1) atoms. In the fourth Se site, Se(4) is bonded in a rectangular see-saw-like geometry to one Cr(3), two equivalent Cr(1), and one Cu(1) atom. In the fifth Se site, Se(5) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(2) and one Co(1) atom. In the sixth Se site, Se(6) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(3), and one Co(1) atom.