MgFeCuS2 is Modderite-derived structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent Cu(1) and three equivalent S(1) atoms. Fe(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form edge-sharing FeS6 octahedra. Cu(1) is bonded in a 6-coordinate geometry to three equivalent Mg(1) and three equivalent S(2) atoms. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to three equivalent Mg(1) and three equivalent Fe(1) atoms. In the second S site, S(2) is bonded in a 6-coordinate geometry to three equivalent Fe(1) and three equivalent Cu(1) atoms.
MgFeCuS2 is Modderite-derived structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent Cu(1) and three equivalent S(1) atoms. All Mg(1)-Cu(1) bond lengths are 2.77 Å. All Mg(1)-S(1) bond lengths are 2.69 Å. Fe(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form edge-sharing FeS6 octahedra. All Fe(1)-S(1) bond lengths are 2.32 Å. All Fe(1)-S(2) bond lengths are 2.28 Å. Cu(1) is bonded in a 6-coordinate geometry to three equivalent Mg(1) and three equivalent S(2) atoms. All Cu(1)-S(2) bond lengths are 2.49 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to three equivalent Mg(1) and three equivalent Fe(1) atoms. In the second S site, S(2) is bonded in a 6-coordinate geometry to three equivalent Fe(1) and three equivalent Cu(1) atoms.