Mg(FeS2)2 crystallizes in the orthorhombic Imma space group. Mg(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form MgS6 octahedra that share corners with six equivalent Fe(2)S6 octahedra, edges with two equivalent Mg(1)S6 octahedra, edges with two equivalent Fe(2)S6 octahedra, and edges with four equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form FeS6 octahedra that share edges with two equivalent Fe(1)S6 octahedra, edges with four equivalent Mg(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) and four equivalent S(2) atoms to form FeS6 octahedra that share corners with six equivalent Mg(1)S6 octahedra, edges with two equivalent Mg(1)S6 octahedra, edges with two equivalent Fe(2)S6 octahedra, and edges with four equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), and two equivalent Fe(1) atoms. In the second S site, S(2) is bonded to two equivalent Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form a mixture of corner and edge-sharing SMg2Fe3 square pyramids.
Mg(FeS2)2 crystallizes in the orthorhombic Imma space group. Mg(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form MgS6 octahedra that share corners with six equivalent Fe(2)S6 octahedra, edges with two equivalent Mg(1)S6 octahedra, edges with two equivalent Fe(2)S6 octahedra, and edges with four equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. Both Mg(1)-S(1) bond lengths are 2.51 Å. All Mg(1)-S(2) bond lengths are 2.53 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form FeS6 octahedra that share edges with two equivalent Fe(1)S6 octahedra, edges with four equivalent Mg(1)S6 octahedra, and edges with four equivalent Fe(2)S6 octahedra. Both Fe(1)-S(2) bond lengths are 2.33 Å. All Fe(1)-S(1) bond lengths are 2.32 Å. In the second Fe site, Fe(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form FeS6 octahedra that share corners with six equivalent Mg(1)S6 octahedra, edges with two equivalent Mg(1)S6 octahedra, edges with two equivalent Fe(2)S6 octahedra, and edges with four equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 6-12°. Both Fe(2)-S(1) bond lengths are 2.41 Å. All Fe(2)-S(2) bond lengths are 2.45 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), and two equivalent Fe(1) atoms. In the second S site, S(2) is bonded to two equivalent Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form a mixture of corner and edge-sharing SMg2Fe3 square pyramids.