Mg2WFe3S8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with three equivalent W(1)S6 octahedra, corners with three equivalent Fe(1)S6 octahedra, and corners with six equivalent Fe(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-60°. W(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form WS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Fe(1)S6 octahedra, and edges with four equivalent Fe(2)S6 octahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent S(3) and four equivalent S(2) atoms to form FeS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent W(1)S6 octahedra, and edges with four equivalent Fe(2)S6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form FeS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent W(1)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra, and edges with two equivalent Fe(2)S6 octahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one W(1), and two equivalent Fe(2) atoms to form distorted SMgFe2W trigonal pyramids that share corners with three equivalent S(3)MgFe3 tetrahedra, corners with three equivalent S(1)MgFe2W trigonal pyramids, corners with six equivalent S(2)MgFe2W trigonal pyramids,  an edgeedge with one S(3)MgFe3 tetrahedra, and edges with two equivalent S(2)MgFe2W trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one W(1), one Fe(1), and one Fe(2) atom to form distorted SMgFe2W trigonal pyramids that share corners with three equivalent S(3)MgFe3 tetrahedra, corners with three equivalent S(1)MgFe2W trigonal pyramids, corners with six equivalent S(2)MgFe2W trigonal pyramids,  an edgeedge with one S(3)MgFe3 tetrahedra,  an edgeedge with one S(1)MgFe2W trigonal pyramid, and  an edgeedge with one S(2)MgFe2W trigonal pyramid. In the third S site, S(3) is bonded to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted SMgFe3 tetrahedra that share corners with three equivalent S(3)MgFe3 tetrahedra, corners with three equivalent S(1)MgFe2W trigonal pyramids, corners with six equivalent S(2)MgFe2W trigonal pyramids,  an edgeedge with one S(1)MgFe2W trigonal pyramid, and edges with two equivalent S(2)MgFe2W trigonal pyramids.
Mg2WFe3S8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with three equivalent W(1)S6 octahedra, corners with three equivalent Fe(1)S6 octahedra, and corners with six equivalent Fe(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-60°. The Mg(1)-S(1) bond length is 2.40 Å. The Mg(1)-S(3) bond length is 2.40 Å. Both Mg(1)-S(2) bond lengths are 2.41 Å. W(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form WS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Fe(1)S6 octahedra, and edges with four equivalent Fe(2)S6 octahedra. Both W(1)-S(1) bond lengths are 2.42 Å. All W(1)-S(2) bond lengths are 2.42 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent S(3) and four equivalent S(2) atoms to form FeS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent W(1)S6 octahedra, and edges with four equivalent Fe(2)S6 octahedra. Both Fe(1)-S(3) bond lengths are 2.40 Å. All Fe(1)-S(2) bond lengths are 2.48 Å. In the second Fe site, Fe(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form FeS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent W(1)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra, and edges with two equivalent Fe(2)S6 octahedra. Both Fe(2)-S(1) bond lengths are 2.48 Å. Both Fe(2)-S(2) bond lengths are 2.48 Å. Both Fe(2)-S(3) bond lengths are 2.40 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one W(1), and two equivalent Fe(2) atoms to form distorted SMgFe2W trigonal pyramids that share corners with three equivalent S(3)MgFe3 tetrahedra, corners with three equivalent S(1)MgFe2W trigonal pyramids, corners with six equivalent S(2)MgFe2W trigonal pyramids,  an edgeedge with one S(3)MgFe3 tetrahedra, and edges with two equivalent S(2)MgFe2W trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one W(1), one Fe(1), and one Fe(2) atom to form distorted SMgFe2W trigonal pyramids that share corners with three equivalent S(3)MgFe3 tetrahedra, corners with three equivalent S(1)MgFe2W trigonal pyramids, corners with six equivalent S(2)MgFe2W trigonal pyramids,  an edgeedge with one S(3)MgFe3 tetrahedra,  an edgeedge with one S(1)MgFe2W trigonal pyramid, and  an edgeedge with one S(2)MgFe2W trigonal pyramid. In the third S site, S(3) is bonded to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted SMgFe3 tetrahedra that share corners with three equivalent S(3)MgFe3 tetrahedra, corners with three equivalent S(1)MgFe2W trigonal pyramids, corners with six equivalent S(2)MgFe2W trigonal pyramids,  an edgeedge with one S(1)MgFe2W trigonal pyramid, and edges with two equivalent S(2)MgFe2W trigonal pyramids.