MgV4FeTlS8 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one Tl(1), one S(3), two equivalent S(2), and two equivalent S(6) atoms to form distorted MgTlS5 square pyramids that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(3)S6 octahedra, corners with two equivalent V(4)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, corners with two equivalent S(1)Tl2V3 trigonal bipyramids,  an edgeedge with one V(1)S6 octahedra, edges with two equivalent V(2)S6 octahedra, edges with two equivalent Mg(1)TlS5 square pyramids, and  a faceface with one V(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-50°. There are four inequivalent V sites. In the first V site, V(1) is bonded to one S(1), one S(7), two equivalent S(2), and two equivalent S(4) atoms to form VS6 octahedra that share corners with two equivalent V(3)S6 octahedra, corners with two equivalent V(4)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(1)S6 octahedra, edges with two equivalent V(2)S6 octahedra,  an edgeedge with one Mg(1)TlS5 square pyramid, and  a faceface with one V(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. In the second V site, V(2) is bonded to one S(2), one S(8), two equivalent S(1), and two equivalent S(3) atoms to form VS6 octahedra that share corners with two equivalent V(3)S6 octahedra, corners with two equivalent V(4)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, edges with two equivalent V(1)S6 octahedra, edges with two equivalent V(2)S6 octahedra, edges with two equivalent Mg(1)TlS5 square pyramids, and  a faceface with one V(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-55°. In the third V site, V(3) is bonded to one S(3), one S(7), two equivalent S(4), and two equivalent S(6) atoms to form VS6 octahedra that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(2)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(3)S6 octahedra, edges with two equivalent V(4)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra,  a faceface with one V(1)S6 octahedra, and  a faceface with one Mg(1)TlS5 square pyramid. The corner-sharing octahedral tilt angles range from 49-53°. In the fourth V site, V(4) is bonded to one S(4), one S(8), two equivalent S(3), and two equivalent S(5) atoms to form distorted VS6 octahedra that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(2)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(3)S6 octahedra, edges with two equivalent V(4)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra, and  a faceface with one V(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. Fe(1) is bonded to one S(5), one S(6), two equivalent S(7), and two equivalent S(8) atoms to form distorted FeS6 octahedra that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(2)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(3)S6 octahedra, edges with two equivalent V(4)S6 octahedra, and edges with two equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. Tl(1) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent S(1), and two equivalent S(5) atoms. There are eight inequivalent S sites. In the first S site, S(1) is bonded to one V(1), two equivalent V(2), and two equivalent Tl(1) atoms to form distorted STl2V3 trigonal bipyramids that share corners with two equivalent S(3)MgV5 pentagonal pyramids, corners with two equivalent Mg(1)TlS5 square pyramids, corners with two equivalent S(4)V5 square pyramids, corners with two equivalent S(8)V2Fe2 trigonal pyramids,  an edgeedge with one S(3)MgV5 pentagonal pyramid, edges with two equivalent S(2)Mg2V3 square pyramids, and edges with two equivalent S(1)Tl2V3 trigonal bipyramids. In the second S site, S(2) is bonded to two equivalent Mg(1), one V(2), and two equivalent V(1) atoms to form SMg2V3 square pyramids that share corners with two equivalent S(6)Mg2V2Fe square pyramids, corners with two equivalent S(4)V5 square pyramids,  a cornercorner with one S(8)V2Fe2 trigonal pyramid, edges with two equivalent S(3)MgV5 pentagonal pyramids,  an edgeedge with one S(6)Mg2V2Fe square pyramid,  an edgeedge with one S(4)V5 square pyramid, edges with two equivalent S(2)Mg2V3 square pyramids, and edges with two equivalent S(1)Tl2V3 trigonal bipyramids. In the third S site, S(3) is bonded to one Mg(1), one V(3), two equivalent V(2), and two equivalent V(4) atoms to form distorted SMgV5 pentagonal pyramids that share corners with two equivalent S(1)Tl2V3 trigonal bipyramids, edges with two equivalent S(3)MgV5 pentagonal pyramids, edges with two equivalent S(6)Mg2V2Fe square pyramids, edges with two equivalent S(2)Mg2V3 square pyramids, edges with two equivalent S(4)V5 square pyramids,  an edgeedge with one S(1)Tl2V3 trigonal bipyramid, and edges with two equivalent S(8)V2Fe2 trigonal pyramids. In the fourth S site, S(4) is bonded to one V(4), two equivalent V(1), and two equivalent V(3) atoms to form distorted SV5 square pyramids that share corners with two equivalent S(6)Mg2V2Fe square pyramids, corners with two equivalent S(2)Mg2V3 square pyramids, corners with two equivalent S(1)Tl2V3 trigonal bipyramids,  a cornercorner with one S(8)V2Fe2 trigonal pyramid, edges with two equivalent S(3)MgV5 pentagonal pyramids,  an edgeedge with one S(6)Mg2V2Fe square pyramid,  an edgeedge with one S(2)Mg2V3 square pyramid, and edges with two equivalent S(4)V5 square pyramids. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent V(4), one Fe(1), and two equivalent Tl(1) atoms. In the sixth S site, S(6) is bonded to two equivalent Mg(1), two equivalent V(3), and one Fe(1) atom to form distorted SMg2V2Fe square pyramids that share corners with two equivalent S(2)Mg2V3 square pyramids, corners with two equivalent S(4)V5 square pyramids, corners with two equivalent S(8)V2Fe2 trigonal pyramids, edges with two equivalent S(3)MgV5 pentagonal pyramids,  an edgeedge with one S(2)Mg2V3 square pyramid,  an edgeedge with one S(4)V5 square pyramid, and edges with two equivalent S(6)Mg2V2Fe square pyramids. In the seventh S site, S(7) is bonded in a distorted rectangular see-saw-like geometry to one V(1), one V(3), and two equivalent Fe(1) atoms. In the eighth S site, S(8) is bonded to one V(2), one V(4), and two equivalent Fe(1) atoms to form distorted SV2Fe2 trigonal pyramids that share  a cornercorner with one S(2)Mg2V3 square pyramid,  a cornercorner with one S(4)V5 square pyramid, corners with two equivalent S(6)Mg2V2Fe square pyramids, corners with two equivalent S(1)Tl2V3 trigonal bipyramids, corners with two equivalent S(8)V2Fe2 trigonal pyramids, and edges with two equivalent S(3)MgV5 pentagonal pyramids.
MgV4FeTlS8 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one Tl(1), one S(3), two equivalent S(2), and two equivalent S(6) atoms to form distorted MgTlS5 square pyramids that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(3)S6 octahedra, corners with two equivalent V(4)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, corners with two equivalent S(1)Tl2V3 trigonal bipyramids,  an edgeedge with one V(1)S6 octahedra, edges with two equivalent V(2)S6 octahedra, edges with two equivalent Mg(1)TlS5 square pyramids, and  a faceface with one V(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-50°. The Mg(1)-Tl(1) bond length is 3.09 Å. The Mg(1)-S(3) bond length is 2.54 Å. Both Mg(1)-S(2) bond lengths are 2.51 Å. Both Mg(1)-S(6) bond lengths are 2.55 Å. There are four inequivalent V sites. In the first V site, V(1) is bonded to one S(1), one S(7), two equivalent S(2), and two equivalent S(4) atoms to form VS6 octahedra that share corners with two equivalent V(3)S6 octahedra, corners with two equivalent V(4)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(1)S6 octahedra, edges with two equivalent V(2)S6 octahedra,  an edgeedge with one Mg(1)TlS5 square pyramid, and  a faceface with one V(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. The V(1)-S(1) bond length is 2.46 Å. The V(1)-S(7) bond length is 2.49 Å. Both V(1)-S(2) bond lengths are 2.50 Å. Both V(1)-S(4) bond lengths are 2.45 Å. In the second V site, V(2) is bonded to one S(2), one S(8), two equivalent S(1), and two equivalent S(3) atoms to form VS6 octahedra that share corners with two equivalent V(3)S6 octahedra, corners with two equivalent V(4)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, edges with two equivalent V(1)S6 octahedra, edges with two equivalent V(2)S6 octahedra, edges with two equivalent Mg(1)TlS5 square pyramids, and  a faceface with one V(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-55°. The V(2)-S(2) bond length is 2.53 Å. The V(2)-S(8) bond length is 2.45 Å. Both V(2)-S(1) bond lengths are 2.40 Å. Both V(2)-S(3) bond lengths are 2.53 Å. In the third V site, V(3) is bonded to one S(3), one S(7), two equivalent S(4), and two equivalent S(6) atoms to form VS6 octahedra that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(2)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(3)S6 octahedra, edges with two equivalent V(4)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra,  a faceface with one V(1)S6 octahedra, and  a faceface with one Mg(1)TlS5 square pyramid. The corner-sharing octahedral tilt angles range from 49-53°. The V(3)-S(3) bond length is 2.55 Å. The V(3)-S(7) bond length is 2.30 Å. Both V(3)-S(4) bond lengths are 2.40 Å. Both V(3)-S(6) bond lengths are 2.48 Å. In the fourth V site, V(4) is bonded to one S(4), one S(8), two equivalent S(3), and two equivalent S(5) atoms to form distorted VS6 octahedra that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(2)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(3)S6 octahedra, edges with two equivalent V(4)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra, and  a faceface with one V(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. The V(4)-S(4) bond length is 2.69 Å. The V(4)-S(8) bond length is 2.25 Å. Both V(4)-S(3) bond lengths are 2.53 Å. Both V(4)-S(5) bond lengths are 2.33 Å. Fe(1) is bonded to one S(5), one S(6), two equivalent S(7), and two equivalent S(8) atoms to form distorted FeS6 octahedra that share corners with two equivalent V(1)S6 octahedra, corners with two equivalent V(2)S6 octahedra, corners with two equivalent Mg(1)TlS5 square pyramids, edges with two equivalent V(3)S6 octahedra, edges with two equivalent V(4)S6 octahedra, and edges with two equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. The Fe(1)-S(5) bond length is 2.21 Å. The Fe(1)-S(6) bond length is 2.43 Å. Both Fe(1)-S(7) bond lengths are 2.37 Å. Both Fe(1)-S(8) bond lengths are 2.30 Å. Tl(1) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent S(1), and two equivalent S(5) atoms. Both Tl(1)-S(1) bond lengths are 3.02 Å. Both Tl(1)-S(5) bond lengths are 3.04 Å. There are eight inequivalent S sites. In the first S site, S(1) is bonded to one V(1), two equivalent V(2), and two equivalent Tl(1) atoms to form distorted STl2V3 trigonal bipyramids that share corners with two equivalent S(3)MgV5 pentagonal pyramids, corners with two equivalent Mg(1)TlS5 square pyramids, corners with two equivalent S(4)V5 square pyramids, corners with two equivalent S(8)V2Fe2 trigonal pyramids,  an edgeedge with one S(3)MgV5 pentagonal pyramid, edges with two equivalent S(2)Mg2V3 square pyramids, and edges with two equivalent S(1)Tl2V3 trigonal bipyramids. In the second S site, S(2) is bonded to two equivalent Mg(1), one V(2), and two equivalent V(1) atoms to form SMg2V3 square pyramids that share corners with two equivalent S(6)Mg2V2Fe square pyramids, corners with two equivalent S(4)V5 square pyramids,  a cornercorner with one S(8)V2Fe2 trigonal pyramid, edges with two equivalent S(3)MgV5 pentagonal pyramids,  an edgeedge with one S(6)Mg2V2Fe square pyramid,  an edgeedge with one S(4)V5 square pyramid, edges with two equivalent S(2)Mg2V3 square pyramids, and edges with two equivalent S(1)Tl2V3 trigonal bipyramids. In the third S site, S(3) is bonded to one Mg(1), one V(3), two equivalent V(2), and two equivalent V(4) atoms to form distorted SMgV5 pentagonal pyramids that share corners with two equivalent S(1)Tl2V3 trigonal bipyramids, edges with two equivalent S(3)MgV5 pentagonal pyramids, edges with two equivalent S(6)Mg2V2Fe square pyramids, edges with two equivalent S(2)Mg2V3 square pyramids, edges with two equivalent S(4)V5 square pyramids,  an edgeedge with one S(1)Tl2V3 trigonal bipyramid, and edges with two equivalent S(8)V2Fe2 trigonal pyramids. In the fourth S site, S(4) is bonded to one V(4), two equivalent V(1), and two equivalent V(3) atoms to form distorted SV5 square pyramids that share corners with two equivalent S(6)Mg2V2Fe square pyramids, corners with two equivalent S(2)Mg2V3 square pyramids, corners with two equivalent S(1)Tl2V3 trigonal bipyramids,  a cornercorner with one S(8)V2Fe2 trigonal pyramid, edges with two equivalent S(3)MgV5 pentagonal pyramids,  an edgeedge with one S(6)Mg2V2Fe square pyramid,  an edgeedge with one S(2)Mg2V3 square pyramid, and edges with two equivalent S(4)V5 square pyramids. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent V(4), one Fe(1), and two equivalent Tl(1) atoms. In the sixth S site, S(6) is bonded to two equivalent Mg(1), two equivalent V(3), and one Fe(1) atom to form distorted SMg2V2Fe square pyramids that share corners with two equivalent S(2)Mg2V3 square pyramids, corners with two equivalent S(4)V5 square pyramids, corners with two equivalent S(8)V2Fe2 trigonal pyramids, edges with two equivalent S(3)MgV5 pentagonal pyramids,  an edgeedge with one S(2)Mg2V3 square pyramid,  an edgeedge with one S(4)V5 square pyramid, and edges with two equivalent S(6)Mg2V2Fe square pyramids. In the seventh S site, S(7) is bonded in a distorted rectangular see-saw-like geometry to one V(1), one V(3), and two equivalent Fe(1) atoms. In the eighth S site, S(8) is bonded to one V(2), one V(4), and two equivalent Fe(1) atoms to form distorted SV2Fe2 trigonal pyramids that share  a cornercorner with one S(2)Mg2V3 square pyramid,  a cornercorner with one S(4)V5 square pyramid, corners with two equivalent S(6)Mg2V2Fe square pyramids, corners with two equivalent S(1)Tl2V3 trigonal bipyramids, corners with two equivalent S(8)V2Fe2 trigonal pyramids, and edges with two equivalent S(3)MgV5 pentagonal pyramids.