Rb2Mg(FeS2)2 crystallizes in the triclinic P1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one Mg(1), one S(4), two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms. Mg(1) is bonded in a 4-coordinate geometry to one Rb(2), one S(1), one S(3), and two equivalent S(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form distorted edge-sharing FeS4 tetrahedra. In the second Fe site, Fe(2) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form distorted edge-sharing FeS4 tetrahedra. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Mg(1), one Fe(1), and one Fe(2) atom. In the second S site, S(2) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Fe(1), and one Fe(2) atom. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Rb(1), two equivalent Rb(2), one Mg(1), one Fe(1), and one Fe(2) atom. In the fourth S site, S(4) is bonded in a 7-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Mg(1), one Fe(1), and one Fe(2) atom.
Rb2Mg(FeS2)2 crystallizes in the triclinic P1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms. The Rb(1)-S(3) bond length is 3.31 Å. There is one shorter (3.37 Å) and one longer (3.46 Å) Rb(1)-S(1) bond length. There is one shorter (3.48 Å) and one longer (3.59 Å) Rb(1)-S(2) bond length. There is one shorter (3.45 Å) and one longer (3.77 Å) Rb(1)-S(4) bond length. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one Mg(1), one S(4), two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms. The Rb(2)-Mg(1) bond length is 3.33 Å. The Rb(2)-S(4) bond length is 3.75 Å. There is one shorter (3.59 Å) and one longer (3.61 Å) Rb(2)-S(1) bond length. There is one shorter (3.41 Å) and one longer (3.64 Å) Rb(2)-S(2) bond length. There is one shorter (3.27 Å) and one longer (3.30 Å) Rb(2)-S(3) bond length. Mg(1) is bonded in a 4-coordinate geometry to one Rb(2), one S(1), one S(3), and two equivalent S(4) atoms. The Mg(1)-S(1) bond length is 2.44 Å. The Mg(1)-S(3) bond length is 2.38 Å. There is one shorter (2.64 Å) and one longer (2.83 Å) Mg(1)-S(4) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form distorted edge-sharing FeS4 tetrahedra. The Fe(1)-S(1) bond length is 2.21 Å. The Fe(1)-S(2) bond length is 2.14 Å. The Fe(1)-S(3) bond length is 2.24 Å. The Fe(1)-S(4) bond length is 2.24 Å. In the second Fe site, Fe(2) is bonded to one S(1), one S(2), one S(3), and one S(4) atom to form distorted edge-sharing FeS4 tetrahedra. The Fe(2)-S(1) bond length is 2.21 Å. The Fe(2)-S(2) bond length is 2.13 Å. The Fe(2)-S(3) bond length is 2.22 Å. The Fe(2)-S(4) bond length is 2.22 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Mg(1), one Fe(1), and one Fe(2) atom. In the second S site, S(2) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Fe(1), and one Fe(2) atom. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Rb(1), two equivalent Rb(2), one Mg(1), one Fe(1), and one Fe(2) atom. In the fourth S site, S(4) is bonded in a 7-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Mg(1), one Fe(1), and one Fe(2) atom.