Rb2Mg(FeO2)2 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 2-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Mg(1) is bonded in an L-shaped geometry to two equivalent O(1) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Fe site, Fe(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) 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 second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(2), two equivalent Rb(1), one Fe(1), and one Fe(2) atom.
Rb2Mg(FeO2)2 crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. Both Rb(1)-O(1) bond lengths are 2.73 Å. All Rb(1)-O(2) bond lengths are 3.15 Å. In the second Rb site, Rb(2) is bonded in a 2-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Both Rb(2)-O(2) bond lengths are 2.84 Å. All Rb(2)-O(1) bond lengths are 3.10 Å. Mg(1) is bonded in an L-shaped geometry to two equivalent O(1) atoms. Both Mg(1)-O(1) bond lengths are 1.91 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Fe(1)-O(1) bond lengths are 2.07 Å. Both Fe(1)-O(2) bond lengths are 2.05 Å. In the second Fe site, Fe(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Fe(2)-O(1) bond lengths are 2.13 Å. Both Fe(2)-O(2) bond lengths are 1.91 Å. There are two inequivalent O sites. In the first O site, O(1) 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 second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(2), two equivalent Rb(1), one Fe(1), and one Fe(2) atom.