MgAl4(HO)12 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one H(10), one O(1), one O(11), one O(6), and one O(7) atom to form MgHO4 trigonal bipyramids that share corners with two equivalent Al(3)O6 octahedra,  a cornercorner with one Al(2)O5 trigonal bipyramid, corners with two equivalent Al(4)O5 trigonal bipyramids, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-52°. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(12), one O(4), one O(7), one O(8), and one O(9) atom to form AlO6 octahedra that share edges with two equivalent Al(3)O6 octahedra,  an edgeedge with one Mg(1)HO4 trigonal bipyramid, and  an edgeedge with one Al(2)O5 trigonal bipyramid. In the second Al site, Al(2) is bonded to one O(10), one O(2), one O(3), one O(7), and one O(8) atom to form AlO5 trigonal bipyramids that share  a cornercorner with one Mg(1)HO4 trigonal bipyramid, corners with two equivalent Al(4)O5 trigonal bipyramids, and  an edgeedge with one Al(1)O6 octahedra. In the third Al site, Al(3) is bonded to one O(1), one O(12), one O(4), one O(5), one O(6), and one O(9) atom to form AlO6 octahedra that share corners with two equivalent Mg(1)HO4 trigonal bipyramids, edges with two equivalent Al(1)O6 octahedra, and  an edgeedge with one Al(4)O5 trigonal bipyramid. In the fourth Al site, Al(4) is bonded to one O(10), one O(11), one O(3), one O(5), and one O(6) atom to form distorted AlO5 trigonal bipyramids that share corners with two equivalent Mg(1)HO4 trigonal bipyramids, corners with two equivalent Al(2)O5 trigonal bipyramids, and  an edgeedge with one Al(3)O6 octahedra. There are twelve inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(3) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(4) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(6) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(7) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(8) atom. In the ninth H site, H(9) is bonded in a single-bond geometry to one O(9) atom. In the tenth H site, H(10) is bonded in a single-bond geometry to one Mg(1) atom. In the eleventh H site, H(11) is bonded in a single-bond geometry to one O(11) atom. In the twelfth H site, H(12) is bonded in a single-bond geometry to one O(12) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Mg(1), one Al(1), one Al(3), and one H(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one Al(2) and one H(2) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Al(2), one Al(4), and one H(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Al(1), one Al(3), and one H(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Al(3), one Al(4), and one H(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Mg(1), one Al(3), one Al(4), and one H(6) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Mg(1), one Al(1), one Al(2), and one H(7) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Al(1), one Al(2), and one H(8) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(3), and one H(9) atom. In the tenth O site, O(10) is bonded in a distorted bent 120 degrees geometry to one Al(2) and one Al(4) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one Mg(1), one Al(4), and one H(11) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Al(1), one Al(3), and one H(12) atom.
MgAl4(HO)12 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one H(10), one O(1), one O(11), one O(6), and one O(7) atom to form MgHO4 trigonal bipyramids that share corners with two equivalent Al(3)O6 octahedra,  a cornercorner with one Al(2)O5 trigonal bipyramid, corners with two equivalent Al(4)O5 trigonal bipyramids, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-52°. The Mg(1)-H(10) bond length is 1.88 Å. The Mg(1)-O(1) bond length is 2.08 Å. The Mg(1)-O(11) bond length is 2.04 Å. The Mg(1)-O(6) bond length is 2.08 Å. The Mg(1)-O(7) bond length is 2.18 Å. There are four inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(12), one O(4), one O(7), one O(8), and one O(9) atom to form AlO6 octahedra that share edges with two equivalent Al(3)O6 octahedra,  an edgeedge with one Mg(1)HO4 trigonal bipyramid, and  an edgeedge with one Al(2)O5 trigonal bipyramid. The Al(1)-O(1) bond length is 1.97 Å. The Al(1)-O(12) bond length is 1.90 Å. The Al(1)-O(4) bond length is 1.86 Å. The Al(1)-O(7) bond length is 2.02 Å. The Al(1)-O(8) bond length is 1.89 Å. The Al(1)-O(9) bond length is 1.88 Å. In the second Al site, Al(2) is bonded to one O(10), one O(2), one O(3), one O(7), and one O(8) atom to form AlO5 trigonal bipyramids that share  a cornercorner with one Mg(1)HO4 trigonal bipyramid, corners with two equivalent Al(4)O5 trigonal bipyramids, and  an edgeedge with one Al(1)O6 octahedra. The Al(2)-O(10) bond length is 1.77 Å. The Al(2)-O(2) bond length is 1.81 Å. The Al(2)-O(3) bond length is 1.98 Å. The Al(2)-O(7) bond length is 1.92 Å. The Al(2)-O(8) bond length is 1.91 Å. In the third Al site, Al(3) is bonded to one O(1), one O(12), one O(4), one O(5), one O(6), and one O(9) atom to form AlO6 octahedra that share corners with two equivalent Mg(1)HO4 trigonal bipyramids, edges with two equivalent Al(1)O6 octahedra, and  an edgeedge with one Al(4)O5 trigonal bipyramid. The Al(3)-O(1) bond length is 2.02 Å. The Al(3)-O(12) bond length is 1.87 Å. The Al(3)-O(4) bond length is 1.87 Å. The Al(3)-O(5) bond length is 1.89 Å. The Al(3)-O(6) bond length is 2.05 Å. The Al(3)-O(9) bond length is 1.91 Å. In the fourth Al site, Al(4) is bonded to one O(10), one O(11), one O(3), one O(5), and one O(6) atom to form distorted AlO5 trigonal bipyramids that share corners with two equivalent Mg(1)HO4 trigonal bipyramids, corners with two equivalent Al(2)O5 trigonal bipyramids, and  an edgeedge with one Al(3)O6 octahedra. The Al(4)-O(10) bond length is 1.75 Å. The Al(4)-O(11) bond length is 1.87 Å. The Al(4)-O(3) bond length is 1.84 Å. The Al(4)-O(5) bond length is 1.81 Å. The Al(4)-O(6) bond length is 2.18 Å. There are twelve inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) atom. The H(1)-O(1) bond length is 1.02 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(2) atom. The H(2)-O(2) bond length is 1.00 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(3) atom. The H(3)-O(3) bond length is 0.98 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(4) atom. The H(4)-O(4) bond length is 1.01 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(5) atom. The H(5)-O(5) bond length is 1.00 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(6) atom. The H(6)-O(6) bond length is 1.00 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(7) atom. The H(7)-O(7) bond length is 1.01 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(8) atom. The H(8)-O(8) bond length is 0.97 Å. In the ninth H site, H(9) is bonded in a single-bond geometry to one O(9) atom. The H(9)-O(9) bond length is 0.98 Å. In the tenth H site, H(10) is bonded in a single-bond geometry to one Mg(1) atom. In the eleventh H site, H(11) is bonded in a single-bond geometry to one O(11) atom. The H(11)-O(11) bond length is 0.98 Å. In the twelfth H site, H(12) is bonded in a single-bond geometry to one O(12) atom. The H(12)-O(12) bond length is 0.98 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Mg(1), one Al(1), one Al(3), and one H(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one Al(2) and one H(2) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Al(2), one Al(4), and one H(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Al(1), one Al(3), and one H(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Al(3), one Al(4), and one H(5) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Mg(1), one Al(3), one Al(4), and one H(6) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Mg(1), one Al(1), one Al(2), and one H(7) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Al(1), one Al(2), and one H(8) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Al(1), one Al(3), and one H(9) atom. In the tenth O site, O(10) is bonded in a distorted bent 120 degrees geometry to one Al(2) and one Al(4) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one Mg(1), one Al(4), and one H(11) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Al(1), one Al(3), and one H(12) atom.