MgFe4(SbS)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent Fe(2), two equivalent Sb(1), two equivalent S(1), and two equivalent S(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Sb(1), two equivalent Sb(2), one S(1), and two equivalent S(2) atoms to form distorted FeSb3S3 octahedra that share corners with two equivalent Sb(2)Fe3S tetrahedra and edges with two equivalent Fe(1)Sb3S3 octahedra. In the second Fe site, Fe(2) is bonded in a 7-coordinate geometry to one Mg(1), 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 4-coordinate geometry to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms. In the second Sb site, Sb(2) is bonded to one Fe(2), two equivalent Fe(1), and one S(2) atom to form distorted SbFe3S tetrahedra that share corners with two equivalent Fe(1)Sb3S3 octahedra and  an edgeedge with one Sb(2)Fe3S tetrahedra. The corner-sharing octahedral tilt angles are 71°. There are two inequivalent S sites. In the first S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms. In the second S site, S(2) is bonded in a 5-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 in a 8-coordinate geometry to two equivalent Fe(2), two equivalent Sb(1), two equivalent S(1), and two equivalent S(2) atoms. Both Mg(1)-Fe(2) bond lengths are 2.57 Å. Both Mg(1)-Sb(1) bond lengths are 2.68 Å. Both Mg(1)-S(1) bond lengths are 2.36 Å. Both Mg(1)-S(2) bond lengths are 2.64 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Sb(1), two equivalent Sb(2), one S(1), and two equivalent S(2) atoms to form distorted FeSb3S3 octahedra that share corners with two equivalent Sb(2)Fe3S tetrahedra and edges with two equivalent Fe(1)Sb3S3 octahedra. The Fe(1)-Sb(1) bond length is 2.53 Å. There is one shorter (2.60 Å) and one longer (2.74 Å) Fe(1)-Sb(2) bond length. The Fe(1)-S(1) bond length is 2.26 Å. There is one shorter (2.28 Å) and one longer (2.36 Å) Fe(1)-S(2) bond length. In the second Fe site, Fe(2) is bonded in a 7-coordinate geometry to one Mg(1), one Sb(2), two equivalent Sb(1), one S(2), and two equivalent S(1) atoms. The Fe(2)-Sb(2) bond length is 2.57 Å. There is one shorter (2.51 Å) and one longer (2.74 Å) Fe(2)-Sb(1) bond length. The Fe(2)-S(2) bond length is 2.42 Å. There is one shorter (2.23 Å) and one longer (2.33 Å) Fe(2)-S(1) bond length. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms. In the second Sb site, Sb(2) is bonded to one Fe(2), two equivalent Fe(1), and one S(2) atom to form distorted SbFe3S tetrahedra that share corners with two equivalent Fe(1)Sb3S3 octahedra and  an edgeedge with one Sb(2)Fe3S tetrahedra. The corner-sharing octahedral tilt angles are 71°. The Sb(2)-S(2) bond length is 2.77 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(2), two equivalent Fe(1), and one Sb(2) atom.