Mg3Cu(SnS4)2 is Spinel-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with six equivalent Mg(2)S6 octahedra and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 53-62°. In the second Mg site, Mg(2) is bonded to one S(1), one S(3), two equivalent S(2), and two equivalent S(4) atoms to form MgS6 octahedra that share corners with three equivalent Mg(1)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, edges with two equivalent Mg(2)S6 octahedra, and edges with four equivalent Sn(1)S6 octahedra. Cu(1) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form CuS4 tetrahedra that share corners with six equivalent Mg(2)S6 octahedra and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 52-59°. Sn(1) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(3) atoms to form SnS6 octahedra that share corners with three equivalent Mg(1)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, edges with two equivalent Sn(1)S6 octahedra, and edges with four equivalent Mg(2)S6 octahedra. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), and two equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(2), and one Sn(1) atom. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Cu(1), and two equivalent Sn(1) atoms. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2), one Cu(1), and one Sn(1) atom.
Mg3Cu(SnS4)2 is Spinel-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with six equivalent Mg(2)S6 octahedra and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 53-62°. Both Mg(1)-S(1) bond lengths are 2.48 Å. Both Mg(1)-S(2) bond lengths are 2.41 Å. In the second Mg site, Mg(2) is bonded to one S(1), one S(3), two equivalent S(2), and two equivalent S(4) atoms to form MgS6 octahedra that share corners with three equivalent Mg(1)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, edges with two equivalent Mg(2)S6 octahedra, and edges with four equivalent Sn(1)S6 octahedra. The Mg(2)-S(1) bond length is 2.56 Å. The Mg(2)-S(3) bond length is 2.60 Å. Both Mg(2)-S(2) bond lengths are 2.56 Å. Both Mg(2)-S(4) bond lengths are 2.61 Å. Cu(1) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form CuS4 tetrahedra that share corners with six equivalent Mg(2)S6 octahedra and corners with six equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 52-59°. Both Cu(1)-S(3) bond lengths are 2.38 Å. Both Cu(1)-S(4) bond lengths are 2.33 Å. Sn(1) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(3) atoms to form SnS6 octahedra that share corners with three equivalent Mg(1)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, edges with two equivalent Sn(1)S6 octahedra, and edges with four equivalent Mg(2)S6 octahedra. The Sn(1)-S(2) bond length is 2.53 Å. The Sn(1)-S(4) bond length is 2.55 Å. Both Sn(1)-S(1) bond lengths are 2.61 Å. Both Sn(1)-S(3) bond lengths are 2.64 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), and two equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(2), and one Sn(1) atom. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Cu(1), and two equivalent Sn(1) atoms. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2), one Cu(1), and one Sn(1) atom.