MgFe2(HO2)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted MgO5 trigonal bipyramids that share corners with four equivalent Mg(1)O5 trigonal bipyramids and edges with four equivalent Fe(2)O6 octahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 7-coordinate geometry to one H(1), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with four equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 15°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Fe(1) and one O(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), two equivalent Fe(1), and two equivalent Fe(2) atoms to form a mixture of distorted edge and corner-sharing OMg2Fe4 octahedra. The corner-sharing octahedral tilt angles are 15°. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Fe(1) and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Fe(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Mg(1), two equivalent Fe(2), and one H(2) atom.
MgFe2(HO2)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(4) atoms to form distorted MgO5 trigonal bipyramids that share corners with four equivalent Mg(1)O5 trigonal bipyramids and edges with four equivalent Fe(2)O6 octahedra. The Mg(1)-O(3) bond length is 2.03 Å. There is one shorter (2.03 Å) and one longer (2.05 Å) Mg(1)-O(1) bond length. There is one shorter (2.11 Å) and one longer (2.15 Å) Mg(1)-O(4) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 7-coordinate geometry to one H(1), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Fe(1)-H(1) bond length is 2.25 Å. There is one shorter (2.34 Å) and one longer (2.57 Å) Fe(1)-O(1) bond length. There is one shorter (2.06 Å) and one longer (2.23 Å) Fe(1)-O(2) bond length. There is one shorter (2.18 Å) and one longer (2.23 Å) Fe(1)-O(3) bond length. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with four equivalent Mg(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 15°. Both Fe(2)-O(1) bond lengths are 2.14 Å. There is one shorter (2.04 Å) and one longer (2.17 Å) Fe(2)-O(2) bond length. There is one shorter (2.22 Å) and one longer (2.36 Å) Fe(2)-O(4) bond length. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one Fe(1) and 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 one O(4) atom. The H(2)-O(4) bond length is 0.98 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), two equivalent Fe(1), and two equivalent Fe(2) atoms to form a mixture of distorted edge and corner-sharing OMg2Fe4 octahedra. The corner-sharing octahedral tilt angles are 15°. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to two equivalent Fe(1) and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Fe(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent Mg(1), two equivalent Fe(2), and one H(2) atom.