MgCo2(HO2)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 9-coordinate geometry to three equivalent H(1) and six equivalent O(1) atoms. Co(1) is bonded to one O(1) and three equivalent O(2) atoms to form corner-sharing CoO4 tetrahedra. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted linear geometry to three equivalent Mg(1) and two equivalent O(1) atoms. In the second H site, H(2) is bonded in a linear geometry to two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent Mg(1), one Co(1), and one H(1) atom. In the second O site, O(2) is bonded to three equivalent Co(1) and one H(2) atom to form corner-sharing OCo3H tetrahedra.
MgCo2(HO2)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 9-coordinate geometry to three equivalent H(1) and six equivalent O(1) atoms. There are two shorter (1.90 Å) and one longer (1.91 Å) Mg(1)-H(1) bond length. There are two shorter (2.22 Å) and four longer (2.23 Å) Mg(1)-O(1) bond lengths. Co(1) is bonded to one O(1) and three equivalent O(2) atoms to form corner-sharing CoO4 tetrahedra. The Co(1)-O(1) bond length is 1.98 Å. All Co(1)-O(2) bond lengths are 2.01 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted linear geometry to three equivalent Mg(1) and two equivalent O(1) atoms. Both H(1)-O(1) bond lengths are 1.16 Å. In the second H site, H(2) is bonded in a linear geometry to two equivalent O(2) atoms. Both H(2)-O(2) bond lengths are 1.22 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent Mg(1), one Co(1), and one H(1) atom. In the second O site, O(2) is bonded to three equivalent Co(1) and one H(2) atom to form corner-sharing OCo3H tetrahedra.