Rb8Mg(FeO4)2 crystallizes in the triclinic P-1 space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 4-coordinate geometry to one O(3), one O(4), and two equivalent O(1) atoms. In the second Rb site, Rb(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form RbO4 tetrahedra that share corners with four equivalent Fe(1)O4 tetrahedra and edges with two equivalent Rb(2)O4 tetrahedra. In the third Rb site, Rb(3) is bonded in a 4-coordinate geometry to one O(2), one O(4), and two equivalent O(1) atoms. In the fourth Rb site, Rb(4) is bonded in a 4-coordinate geometry to one O(3), one O(4), and two equivalent O(2) atoms. Mg(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. Fe(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form FeO4 tetrahedra that share corners with four equivalent Rb(2)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Rb(1), two equivalent Rb(3), one Mg(1), and one Fe(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Rb(3), two equivalent Rb(2), two equivalent Rb(4), and one Fe(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(1), one Rb(4), one Mg(1), and one Fe(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(3), one Rb(4), two equivalent Rb(2), and one Fe(1) atom.
Rb8Mg(FeO4)2 crystallizes in the triclinic P-1 space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 4-coordinate geometry to one O(3), one O(4), and two equivalent O(1) atoms. The Rb(1)-O(3) bond length is 2.83 Å. The Rb(1)-O(4) bond length is 3.10 Å. There is one shorter (2.73 Å) and one longer (2.80 Å) Rb(1)-O(1) bond length. In the second Rb site, Rb(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form RbO4 tetrahedra that share corners with four equivalent Fe(1)O4 tetrahedra and edges with two equivalent Rb(2)O4 tetrahedra. There is one shorter (2.74 Å) and one longer (2.77 Å) Rb(2)-O(2) bond length. There is one shorter (2.85 Å) and one longer (2.95 Å) Rb(2)-O(4) bond length. In the third Rb site, Rb(3) is bonded in a 4-coordinate geometry to one O(2), one O(4), and two equivalent O(1) atoms. The Rb(3)-O(2) bond length is 2.77 Å. The Rb(3)-O(4) bond length is 3.04 Å. There is one shorter (2.85 Å) and one longer (3.08 Å) Rb(3)-O(1) bond length. In the fourth Rb site, Rb(4) is bonded in a 4-coordinate geometry to one O(3), one O(4), and two equivalent O(2) atoms. The Rb(4)-O(3) bond length is 2.95 Å. The Rb(4)-O(4) bond length is 3.11 Å. There is one shorter (2.83 Å) and one longer (3.19 Å) Rb(4)-O(2) bond length. Mg(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. Both Mg(1)-O(1) bond lengths are 2.08 Å. Both Mg(1)-O(3) bond lengths are 2.13 Å. Fe(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form FeO4 tetrahedra that share corners with four equivalent Rb(2)O4 tetrahedra. The Fe(1)-O(1) bond length is 1.95 Å. The Fe(1)-O(2) bond length is 1.90 Å. The Fe(1)-O(3) bond length is 1.96 Å. The Fe(1)-O(4) bond length is 1.92 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Rb(1), two equivalent Rb(3), one Mg(1), and one Fe(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Rb(3), two equivalent Rb(2), two equivalent Rb(4), and one Fe(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Rb(1), one Rb(4), one Mg(1), and one Fe(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Rb(1), one Rb(3), one Rb(4), two equivalent Rb(2), and one Fe(1) atom.