K2Mg(FeO2)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 3-coordinate geometry to three equivalent O(1) atoms. Mg(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. Fe(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing FeO4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent K(1) and two equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OK3Fe2 trigonal bipyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and two equivalent Fe(1) atoms.
K2Mg(FeO2)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 3-coordinate geometry to three equivalent O(1) atoms. There are two shorter (2.56 Å) and one longer (2.79 Å) K(1)-O(1) bond length. Mg(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Mg(1)-O(2) bond lengths are 2.06 Å. Fe(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing FeO4 tetrahedra. There is one shorter (1.96 Å) and one longer (1.98 Å) Fe(1)-O(1) bond length. Both Fe(1)-O(2) bond lengths are 2.18 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent K(1) and two equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OK3Fe2 trigonal bipyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and two equivalent Fe(1) atoms.