Mg3H2(SO5)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra and corners with four equivalent S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. In the second Mg site, Mg(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent S(1)O4 tetrahedra, and faces with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. H(1) is bonded in a single-bond geometry to one O(1) atom. S(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form SO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-43°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(2), and one H(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Mg(2) and one S(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Mg(2) and one S(1) atom.
Mg3H2(SO5)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra and corners with four equivalent S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. Both Mg(1)-O(1) bond lengths are 2.12 Å. All Mg(1)-O(3) bond lengths are 2.14 Å. In the second Mg site, Mg(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent S(1)O4 tetrahedra, and faces with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. Both Mg(2)-O(1) bond lengths are 2.07 Å. Both Mg(2)-O(2) bond lengths are 2.07 Å. Both Mg(2)-O(4) bond lengths are 2.11 Å. H(1) is bonded in a single-bond geometry to one O(1) atom. The H(1)-O(1) bond length is 0.98 Å. S(1) is bonded to one O(2), one O(4), and two equivalent O(3) atoms to form SO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-43°. The S(1)-O(2) bond length is 1.51 Å. The S(1)-O(4) bond length is 1.50 Å. Both S(1)-O(3) bond lengths are 1.47 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Mg(1), two equivalent Mg(2), and one H(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Mg(2) and one S(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Mg(2) and one S(1) atom.