MgFe4(SbS)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent Fe(1), two equivalent Sb(1), two equivalent Sb(2), and two equivalent S(2) atoms to form distorted MgFe2Sb4S2 hexagonal bipyramids that share corners with four equivalent S(1)Fe3Sb tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 7-coordinate geometry to one Mg(1), one Sb(1), two equivalent Sb(2), one S(1), and two equivalent S(2) atoms. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one Sb(2), two equivalent Sb(1), one S(2), and two equivalent S(1) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(1), two equivalent Fe(2), and one S(1) atom. In the second Sb site, Sb(2) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(2), two equivalent Fe(1), and one S(2) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Fe(1), two equivalent Fe(2), and one Sb(1) atom to form distorted SFe3Sb tetrahedra that share corners with two equivalent Mg(1)Fe2Sb4S2 hexagonal bipyramids and  an edgeedge with one S(1)Fe3Sb tetrahedra. In the second S site, S(2) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(2), two equivalent Fe(1), and one Sb(2) atom.
MgFe4(SbS)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent Fe(1), two equivalent Sb(1), two equivalent Sb(2), and two equivalent S(2) atoms to form distorted MgFe2Sb4S2 hexagonal bipyramids that share corners with four equivalent S(1)Fe3Sb tetrahedra. Both Mg(1)-Fe(1) bond lengths are 2.60 Å. Both Mg(1)-Sb(1) bond lengths are 2.83 Å. Both Mg(1)-Sb(2) bond lengths are 2.66 Å. Both Mg(1)-S(2) bond lengths are 2.39 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 7-coordinate geometry to one Mg(1), one Sb(1), two equivalent Sb(2), one S(1), and two equivalent S(2) atoms. The Fe(1)-Sb(1) bond length is 2.71 Å. There is one shorter (2.50 Å) and one longer (2.83 Å) Fe(1)-Sb(2) bond length. The Fe(1)-S(1) bond length is 2.30 Å. There is one shorter (2.21 Å) and one longer (2.39 Å) Fe(1)-S(2) bond length. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one Sb(2), two equivalent Sb(1), one S(2), and two equivalent S(1) atoms. The Fe(2)-Sb(2) bond length is 2.56 Å. There is one shorter (2.70 Å) and one longer (2.75 Å) Fe(2)-Sb(1) bond length. The Fe(2)-S(2) bond length is 2.32 Å. There is one shorter (2.21 Å) and one longer (2.29 Å) Fe(2)-S(1) bond length. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(1), two equivalent Fe(2), and one S(1) atom. The Sb(1)-S(1) bond length is 2.68 Å. In the second Sb site, Sb(2) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(2), two equivalent Fe(1), and one S(2) atom. The Sb(2)-S(2) bond length is 3.03 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Fe(1), two equivalent Fe(2), and one Sb(1) atom to form distorted SFe3Sb tetrahedra that share corners with two equivalent Mg(1)Fe2Sb4S2 hexagonal bipyramids and  an edgeedge with one S(1)Fe3Sb tetrahedra. In the second S site, S(2) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(2), two equivalent Fe(1), and one Sb(2) atom.