MgFe2Cu6SnS8 is Aluminum carbonitride-derived structured and crystallizes in the orthorhombic Pmm2 space group. Mg(1) is bonded to two equivalent Cu(3), two equivalent S(2), and two equivalent S(3) atoms to form distorted MgCu2S4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, corners with four equivalent S(2)MgCu3Sn trigonal bipyramids, and edges with four equivalent Cu(1)S4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form FeS4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, edges with two equivalent Fe(2)S4 tetrahedra, and edges with four equivalent Cu(1)S4 tetrahedra. In the second Fe site, Fe(2) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form FeS4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, corners with eight equivalent Cu(1)S4 tetrahedra, and edges with two equivalent Fe(1)S4 tetrahedra. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form distorted CuS4 tetrahedra that share corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, corners with four equivalent Cu(1)S4 tetrahedra,  an edgeedge with one Mg(1)Cu2S4 tetrahedra, and  an edgeedge with one Fe(1)S4 tetrahedra. In the second Cu site, Cu(2) is bonded to two equivalent S(1) and two equivalent S(4) atoms to form CuS4 tetrahedra that share corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, and corners with eight equivalent Cu(1)S4 tetrahedra. In the third Cu site, Cu(3) is bonded in a 6-coordinate geometry to two equivalent Mg(1), two equivalent S(2), and two equivalent S(3) atoms. Sn(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form SnS4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, and corners with eight equivalent Cu(1)S4 tetrahedra. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Cu(2), two equivalent Cu(1), and one Sn(1) atom to form SCu3Sn tetrahedra that share corners with two equivalent S(1)Cu3Sn tetrahedra and corners with four equivalent S(2)MgCu3Sn trigonal bipyramids. In the second S site, S(2) is bonded to one Mg(1), one Cu(3), two equivalent Cu(1), and one Sn(1) atom to form distorted SMgCu3Sn trigonal bipyramids that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with four equivalent S(1)Cu3Sn tetrahedra,  a cornercorner with one S(2)MgCu3Sn trigonal bipyramid, and  an edgeedge with one S(2)MgCu3Sn trigonal bipyramid. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Mg(1), one Fe(1), one Fe(2), one Cu(3), and two equivalent Cu(1) atoms. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one Fe(1), one Fe(2), one Cu(2), and two equivalent Cu(1) atoms.
MgFe2Cu6SnS8 is Aluminum carbonitride-derived structured and crystallizes in the orthorhombic Pmm2 space group. Mg(1) is bonded to two equivalent Cu(3), two equivalent S(2), and two equivalent S(3) atoms to form distorted MgCu2S4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, corners with four equivalent S(2)MgCu3Sn trigonal bipyramids, and edges with four equivalent Cu(1)S4 tetrahedra. Both Mg(1)-Cu(3) bond lengths are 2.75 Å. Both Mg(1)-S(2) bond lengths are 2.42 Å. Both Mg(1)-S(3) bond lengths are 2.40 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form FeS4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, edges with two equivalent Fe(2)S4 tetrahedra, and edges with four equivalent Cu(1)S4 tetrahedra. Both Fe(1)-S(3) bond lengths are 2.36 Å. Both Fe(1)-S(4) bond lengths are 2.35 Å. In the second Fe site, Fe(2) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form FeS4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, corners with eight equivalent Cu(1)S4 tetrahedra, and edges with two equivalent Fe(1)S4 tetrahedra. Both Fe(2)-S(3) bond lengths are 2.32 Å. Both Fe(2)-S(4) bond lengths are 2.30 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form distorted CuS4 tetrahedra that share corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, corners with four equivalent Cu(1)S4 tetrahedra,  an edgeedge with one Mg(1)Cu2S4 tetrahedra, and  an edgeedge with one Fe(1)S4 tetrahedra. The Cu(1)-S(1) bond length is 2.29 Å. The Cu(1)-S(2) bond length is 2.40 Å. The Cu(1)-S(3) bond length is 2.48 Å. The Cu(1)-S(4) bond length is 2.31 Å. In the second Cu site, Cu(2) is bonded to two equivalent S(1) and two equivalent S(4) atoms to form CuS4 tetrahedra that share corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Fe(2)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, and corners with eight equivalent Cu(1)S4 tetrahedra. Both Cu(2)-S(1) bond lengths are 2.30 Å. Both Cu(2)-S(4) bond lengths are 2.35 Å. In the third Cu site, Cu(3) is bonded in a 6-coordinate geometry to two equivalent Mg(1), two equivalent S(2), and two equivalent S(3) atoms. Both Cu(3)-S(2) bond lengths are 2.32 Å. Both Cu(3)-S(3) bond lengths are 2.48 Å. Sn(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form SnS4 tetrahedra that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, and corners with eight equivalent Cu(1)S4 tetrahedra. Both Sn(1)-S(1) bond lengths are 2.45 Å. Both Sn(1)-S(2) bond lengths are 2.53 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Cu(2), two equivalent Cu(1), and one Sn(1) atom to form SCu3Sn tetrahedra that share corners with two equivalent S(1)Cu3Sn tetrahedra and corners with four equivalent S(2)MgCu3Sn trigonal bipyramids. In the second S site, S(2) is bonded to one Mg(1), one Cu(3), two equivalent Cu(1), and one Sn(1) atom to form distorted SMgCu3Sn trigonal bipyramids that share corners with two equivalent Mg(1)Cu2S4 tetrahedra, corners with four equivalent S(1)Cu3Sn tetrahedra,  a cornercorner with one S(2)MgCu3Sn trigonal bipyramid, and  an edgeedge with one S(2)MgCu3Sn trigonal bipyramid. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Mg(1), one Fe(1), one Fe(2), one Cu(3), and two equivalent Cu(1) atoms. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one Fe(1), one Fe(2), one Cu(2), and two equivalent Cu(1) atoms.