MgFe2(HO2)2 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent H(2), one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 7-coordinate geometry to one H(2), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second Fe site, Fe(2) is bonded in a 3-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to two equivalent Mg(1), one Fe(1), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(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 OMgFe4 trigonal bipyramids. In the second O site, O(2) 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 OMgFe4 trigonal bipyramids. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Mg(1), two equivalent Fe(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to two equivalent Mg(1) and one H(2) atom.
MgFe2(HO2)2 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent H(2), one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. Both Mg(1)-H(2) bond lengths are 2.26 Å. The Mg(1)-O(1) bond length is 2.33 Å. The Mg(1)-O(2) bond length is 2.02 Å. Both Mg(1)-O(3) bond lengths are 2.15 Å. Both Mg(1)-O(4) bond lengths are 2.15 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 7-coordinate geometry to one H(2), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Fe(1)-H(2) bond length is 2.26 Å. Both Fe(1)-O(1) bond lengths are 2.10 Å. There is one shorter (2.18 Å) and one longer (2.49 Å) Fe(1)-O(2) bond length. Both Fe(1)-O(3) bond lengths are 2.28 Å. In the second Fe site, Fe(2) is bonded in a 3-coordinate geometry to two equivalent O(1) and two equivalent O(2) atoms. There is one shorter (2.19 Å) and one longer (2.49 Å) Fe(2)-O(1) bond length. Both Fe(2)-O(2) bond lengths are 2.07 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(3) atom. The H(1)-O(3) bond length is 0.99 Å. In the second H site, H(2) is bonded in a single-bond geometry to two equivalent Mg(1), one Fe(1), and one O(4) atom. The H(2)-O(4) bond length is 1.00 Å. There are four inequivalent O sites. In the first O site, O(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 OMgFe4 trigonal bipyramids. In the second O site, O(2) 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 OMgFe4 trigonal bipyramids. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Mg(1), two equivalent Fe(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to two equivalent Mg(1) and one H(2) atom.