MgH6(SO4)4 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra and corners with four equivalent S(2)O4 tetrahedra. There are three inequivalent H sites. In the first H site, H(1) is bonded in a distorted linear geometry to one O(2) and one O(6) atom. In the second H site, H(2) is bonded in a linear geometry to one O(1) and one O(7) atom. In the third H site, H(3) is bonded in a linear geometry to one O(1) and one O(8) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 33°. In the second S site, S(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-34°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(2) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(1) atom. In the third O site, O(6) is bonded in a bent 120 degrees geometry to one H(1) and one S(1) atom. In the fourth O site, O(7) is bonded in a bent 120 degrees geometry to one H(2) and one S(1) atom. In the fifth O site, O(8) is bonded in a bent 120 degrees geometry to one H(3) and one S(1) atom. In the sixth O site, O(1) is bonded in a trigonal planar geometry to one H(2), one H(3), and one S(2) atom. In the seventh O site, O(2) is bonded in a water-like geometry to one H(1) and one S(2) atom. In the eighth O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(2) atom.
MgH6(SO4)4 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form MgO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra and corners with four equivalent S(2)O4 tetrahedra. Both Mg(1)-O(3) bond lengths are 2.09 Å. Both Mg(1)-O(4) bond lengths are 2.06 Å. Both Mg(1)-O(5) bond lengths are 2.12 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a distorted linear geometry to one O(2) and one O(6) atom. The H(1)-O(2) bond length is 1.02 Å. The H(1)-O(6) bond length is 1.59 Å. In the second H site, H(2) is bonded in a linear geometry to one O(1) and one O(7) atom. The H(2)-O(1) bond length is 1.54 Å. The H(2)-O(7) bond length is 1.03 Å. In the third H site, H(3) is bonded in a linear geometry to one O(1) and one O(8) atom. The H(3)-O(1) bond length is 1.55 Å. The H(3)-O(8) bond length is 1.03 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 33°. The S(1)-O(5) bond length is 1.45 Å. The S(1)-O(6) bond length is 1.45 Å. The S(1)-O(7) bond length is 1.54 Å. The S(1)-O(8) bond length is 1.55 Å. In the second S site, S(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-34°. The S(2)-O(1) bond length is 1.49 Å. The S(2)-O(2) bond length is 1.56 Å. The S(2)-O(3) bond length is 1.46 Å. The S(2)-O(4) bond length is 1.46 Å. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(2) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(1) atom. In the third O site, O(6) is bonded in a bent 120 degrees geometry to one H(1) and one S(1) atom. In the fourth O site, O(7) is bonded in a bent 120 degrees geometry to one H(2) and one S(1) atom. In the fifth O site, O(8) is bonded in a bent 120 degrees geometry to one H(3) and one S(1) atom. In the sixth O site, O(1) is bonded in a trigonal planar geometry to one H(2), one H(3), and one S(2) atom. In the seventh O site, O(2) is bonded in a water-like geometry to one H(1) and one S(2) atom. In the eighth O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one S(2) atom.