Mg(Fe2S3)2 crystallizes in the trigonal R-3 space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent Fe(1) and six equivalent S(1) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 7-coordinate geometry to one Mg(1) and six equivalent S(1) atoms. In the second Fe site, Fe(2) is bonded to six equivalent S(1) atoms to form edge-sharing FeS6 octahedra. S(1) is bonded to one Mg(1), two equivalent Fe(1), and two equivalent Fe(2) atoms to form a mixture of distorted corner and edge-sharing SMgFe4 trigonal bipyramids.
Mg(Fe2S3)2 crystallizes in the trigonal R-3 space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent Fe(1) and six equivalent S(1) atoms. Both Mg(1)-Fe(1) bond lengths are 2.54 Å. All Mg(1)-S(1) bond lengths are 2.46 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) and six equivalent S(1) atoms. There are three shorter (2.25 Å) and three longer (2.38 Å) Fe(1)-S(1) bond lengths. In the second Fe site, Fe(2) is bonded to six equivalent S(1) atoms to form edge-sharing FeS6 octahedra. There are three shorter (2.27 Å) and three longer (2.37 Å) Fe(2)-S(1) bond lengths. S(1) is bonded to one Mg(1), two equivalent Fe(1), and two equivalent Fe(2) atoms to form a mixture of distorted corner and edge-sharing SMgFe4 trigonal bipyramids.