Cr8Fe3CuS16 is Spinel-derived structured and crystallizes in the trigonal R3m space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one S(3), one S(7), two equivalent S(1), and two equivalent S(5) atoms to form CrS6 octahedra that share  a cornercorner with one Fe(1)S4 tetrahedra,  a cornercorner with one Fe(3)S4 tetrahedra, corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Cu(1)S4 tetrahedra,  an edgeedge with one Cr(3)S6 octahedra,  an edgeedge with one Cr(4)S6 octahedra, and edges with four equivalent Cr(1)S6 octahedra. In the second Cr site, Cr(2) is bonded to one S(4), one S(8), two equivalent S(2), and two equivalent S(6) atoms to form CrS6 octahedra that share  a cornercorner with one Fe(2)S4 tetrahedra,  a cornercorner with one Cu(1)S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Fe(3)S4 tetrahedra,  an edgeedge with one Cr(3)S6 octahedra,  an edgeedge with one Cr(4)S6 octahedra, and edges with four equivalent Cr(2)S6 octahedra. In the third Cr site, Cr(3) is bonded to three equivalent S(2) and three equivalent S(5) atoms to form CrS6 octahedra that share corners with three equivalent Fe(3)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, edges with three equivalent Cr(1)S6 octahedra, and edges with three equivalent Cr(2)S6 octahedra. In the fourth Cr site, Cr(4) is bonded to three equivalent S(1) and three equivalent S(6) atoms to form CrS6 octahedra that share corners with three equivalent Fe(1)S4 tetrahedra, corners with three equivalent Fe(2)S4 tetrahedra, edges with three equivalent Cr(1)S6 octahedra, and edges with three equivalent Cr(2)S6 octahedra. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one S(7) and three equivalent S(6) atoms to form FeS4 tetrahedra that share corners with three equivalent Cr(1)S6 octahedra, corners with three equivalent Cr(4)S6 octahedra, and corners with six equivalent Cr(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. In the second Fe site, Fe(2) is bonded to one S(4) and three equivalent S(1) atoms to form FeS4 tetrahedra that share corners with three equivalent Cr(2)S6 octahedra, corners with three equivalent Cr(4)S6 octahedra, and corners with six equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. In the third Fe site, Fe(3) is bonded to one S(3) and three equivalent S(2) atoms to form FeS4 tetrahedra that share corners with three equivalent Cr(1)S6 octahedra, corners with three equivalent Cr(3)S6 octahedra, and corners with six equivalent Cr(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. Cu(1) is bonded to one S(8) and three equivalent S(5) atoms to form CuS4 tetrahedra that share corners with three equivalent Cr(2)S6 octahedra, corners with three equivalent Cr(3)S6 octahedra, and corners with six equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 57-58°. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Cr(4), two equivalent Cr(1), and one Fe(2) atom. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Cr(3), two equivalent Cr(2), and one Fe(3) atom. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(1) and one Fe(3) atom. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(2) and one Fe(2) atom. In the fifth S site, S(5) is bonded to one Cr(3), two equivalent Cr(1), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing SCr3Cu trigonal pyramids. In the sixth S site, S(6) is bonded in a rectangular see-saw-like geometry to one Cr(4), two equivalent Cr(2), and one Fe(1) atom. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(1) and one Fe(1) atom. In the eighth S site, S(8) is bonded to three equivalent Cr(2) and one Cu(1) atom to form distorted corner-sharing SCr3Cu trigonal pyramids.
Cr8Fe3CuS16 is Spinel-derived structured and crystallizes in the trigonal R3m space group. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one S(3), one S(7), two equivalent S(1), and two equivalent S(5) atoms to form CrS6 octahedra that share  a cornercorner with one Fe(1)S4 tetrahedra,  a cornercorner with one Fe(3)S4 tetrahedra, corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Cu(1)S4 tetrahedra,  an edgeedge with one Cr(3)S6 octahedra,  an edgeedge with one Cr(4)S6 octahedra, and edges with four equivalent Cr(1)S6 octahedra. The Cr(1)-S(3) bond length is 2.40 Å. The Cr(1)-S(7) bond length is 2.42 Å. Both Cr(1)-S(1) bond lengths are 2.40 Å. Both Cr(1)-S(5) bond lengths are 2.36 Å. In the second Cr site, Cr(2) is bonded to one S(4), one S(8), two equivalent S(2), and two equivalent S(6) atoms to form CrS6 octahedra that share  a cornercorner with one Fe(2)S4 tetrahedra,  a cornercorner with one Cu(1)S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Fe(3)S4 tetrahedra,  an edgeedge with one Cr(3)S6 octahedra,  an edgeedge with one Cr(4)S6 octahedra, and edges with four equivalent Cr(2)S6 octahedra. The Cr(2)-S(4) bond length is 2.40 Å. The Cr(2)-S(8) bond length is 2.37 Å. Both Cr(2)-S(2) bond lengths are 2.40 Å. Both Cr(2)-S(6) bond lengths are 2.42 Å. In the third Cr site, Cr(3) is bonded to three equivalent S(2) and three equivalent S(5) atoms to form CrS6 octahedra that share corners with three equivalent Fe(3)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, edges with three equivalent Cr(1)S6 octahedra, and edges with three equivalent Cr(2)S6 octahedra. All Cr(3)-S(2) bond lengths are 2.41 Å. All Cr(3)-S(5) bond lengths are 2.37 Å. In the fourth Cr site, Cr(4) is bonded to three equivalent S(1) and three equivalent S(6) atoms to form CrS6 octahedra that share corners with three equivalent Fe(1)S4 tetrahedra, corners with three equivalent Fe(2)S4 tetrahedra, edges with three equivalent Cr(1)S6 octahedra, and edges with three equivalent Cr(2)S6 octahedra. All Cr(4)-S(1) bond lengths are 2.41 Å. All Cr(4)-S(6) bond lengths are 2.39 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one S(7) and three equivalent S(6) atoms to form FeS4 tetrahedra that share corners with three equivalent Cr(1)S6 octahedra, corners with three equivalent Cr(4)S6 octahedra, and corners with six equivalent Cr(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. The Fe(1)-S(7) bond length is 2.15 Å. All Fe(1)-S(6) bond lengths are 2.15 Å. In the second Fe site, Fe(2) is bonded to one S(4) and three equivalent S(1) atoms to form FeS4 tetrahedra that share corners with three equivalent Cr(2)S6 octahedra, corners with three equivalent Cr(4)S6 octahedra, and corners with six equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. The Fe(2)-S(4) bond length is 2.16 Å. All Fe(2)-S(1) bond lengths are 2.16 Å. In the third Fe site, Fe(3) is bonded to one S(3) and three equivalent S(2) atoms to form FeS4 tetrahedra that share corners with three equivalent Cr(1)S6 octahedra, corners with three equivalent Cr(3)S6 octahedra, and corners with six equivalent Cr(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 55-56°. The Fe(3)-S(3) bond length is 2.16 Å. All Fe(3)-S(2) bond lengths are 2.16 Å. Cu(1) is bonded to one S(8) and three equivalent S(5) atoms to form CuS4 tetrahedra that share corners with three equivalent Cr(2)S6 octahedra, corners with three equivalent Cr(3)S6 octahedra, and corners with six equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 57-58°. The Cu(1)-S(8) bond length is 2.25 Å. All Cu(1)-S(5) bond lengths are 2.24 Å. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Cr(4), two equivalent Cr(1), and one Fe(2) atom. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Cr(3), two equivalent Cr(2), and one Fe(3) atom. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(1) and one Fe(3) atom. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(2) and one Fe(2) atom. In the fifth S site, S(5) is bonded to one Cr(3), two equivalent Cr(1), and one Cu(1) atom to form a mixture of distorted edge and corner-sharing SCr3Cu trigonal pyramids. In the sixth S site, S(6) is bonded in a rectangular see-saw-like geometry to one Cr(4), two equivalent Cr(2), and one Fe(1) atom. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(1) and one Fe(1) atom. In the eighth S site, S(8) is bonded to three equivalent Cr(2) and one Cu(1) atom to form distorted corner-sharing SCr3Cu trigonal pyramids.