Mg3H22(C7O5)4(CNH2)4 crystallizes in the orthorhombic Pbca space group. The structure consists of sixteen methylamine molecules inside a Mg3H22(C7O5)4 framework. In the Mg3H22(C7O5)4 framework, there are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(10), and two equivalent O(4) atoms to form corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 69°. Both Mg(1)-O(1) bond lengths are 2.03 Å. Both Mg(1)-O(10) bond lengths are 2.18 Å. Both Mg(1)-O(4) bond lengths are 2.01 Å. In the second Mg site, Mg(2) is bonded to one O(10), one O(2), one O(3), one O(5), one O(6), and one O(9) atom to form corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 69°. The Mg(2)-O(10) bond length is 2.16 Å. The Mg(2)-O(2) bond length is 2.05 Å. The Mg(2)-O(3) bond length is 2.11 Å. The Mg(2)-O(5) bond length is 2.05 Å. The Mg(2)-O(6) bond length is 2.08 Å. The Mg(2)-O(9) bond length is 2.22 Å. There are fourteen inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(13), one C(14), and one C(15) atom. The C(1)-C(13) bond length is 1.40 Å. The C(1)-C(14) bond length is 1.40 Å. The C(1)-C(15) bond length is 1.51 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(10), one C(4), and one C(9) atom. The C(2)-C(10) bond length is 1.40 Å. The C(2)-C(4) bond length is 1.40 Å. The C(2)-C(9) bond length is 1.49 Å. In the third C site, C(4) is bonded in a distorted single-bond geometry to one C(2) and one H(6) atom. The C(4)-H(6) bond length is 1.09 Å. In the fourth C site, C(5) is bonded in a trigonal planar geometry to one C(12), one C(13), and one C(6) atom. The C(5)-C(12) bond length is 1.40 Å. The C(5)-C(13) bond length is 1.40 Å. The C(5)-C(6) bond length is 1.48 Å. In the fifth C site, C(6) is bonded in a bent 120 degrees geometry to one C(5), one O(8), and one O(9) atom. The C(6)-O(8) bond length is 1.33 Å. The C(6)-O(9) bond length is 1.25 Å. In the sixth C site, C(7) is bonded in a trigonal planar geometry to one C(10), one C(11), and one C(16) atom. The C(7)-C(10) bond length is 1.40 Å. The C(7)-C(11) bond length is 1.40 Å. The C(7)-C(16) bond length is 1.50 Å. In the seventh C site, C(9) is bonded in a bent 120 degrees geometry to one C(2), one O(1), and one O(3) atom. The C(9)-O(1) bond length is 1.25 Å. The C(9)-O(3) bond length is 1.30 Å. In the eighth C site, C(10) is bonded in a distorted single-bond geometry to one C(2), one C(7), and one H(7) atom. The C(10)-H(7) bond length is 1.08 Å. In the ninth C site, C(11) is bonded in a single-bond geometry to one C(7) and one H(8) atom. The C(11)-H(8) bond length is 1.09 Å. In the tenth C site, C(12) is bonded in a distorted single-bond geometry to one C(5) and one H(9) atom. The C(12)-H(9) bond length is 1.09 Å. In the eleventh C site, C(13) is bonded in a distorted single-bond geometry to one C(1), one C(5), and one H(10) atom. The C(13)-H(10) bond length is 1.09 Å. In the twelfth C site, C(14) is bonded in a distorted single-bond geometry to one C(1) and one H(11) atom. The C(14)-H(11) bond length is 1.09 Å. In the thirteenth C site, C(15) is bonded in a bent 120 degrees geometry to one C(1), one O(4), and one O(5) atom. The C(15)-O(4) bond length is 1.27 Å. The C(15)-O(5) bond length is 1.27 Å. In the fourteenth C site, C(16) is bonded in a distorted bent 120 degrees geometry to one C(7), one O(6), and one O(7) atom. The C(16)-O(6) bond length is 1.28 Å. The C(16)-O(7) bond length is 1.27 Å. There are eleven inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(3) and one O(8) atom. The H(1)-O(3) bond length is 1.61 Å. The H(1)-O(8) bond length is 1.03 Å. In the second H site, H(6) is bonded in a single-bond geometry to one C(4) atom. In the third H site, H(7) is bonded in a single-bond geometry to one C(10) atom. In the fourth H site, H(8) is bonded in a single-bond geometry to one C(11) atom. In the fifth H site, H(9) is bonded in a single-bond geometry to one C(12) atom. In the sixth H site, H(10) is bonded in a single-bond geometry to one C(13) atom. In the seventh H site, H(11) is bonded in a single-bond geometry to one C(14) atom. In the eighth H site, H(12) is bonded in a single-bond geometry to one O(10) atom. The H(12)-O(10) bond length is 0.98 Å. In the ninth H site, H(13) is bonded in a distorted linear geometry to one O(10) and one O(7) atom. The H(13)-O(10) bond length is 1.07 Å. The H(13)-O(7) bond length is 1.45 Å. In the tenth H site, H(14) is bonded in a single-bond geometry to one O(2) atom. The H(14)-O(2) bond length is 0.99 Å. In the eleventh H site, H(15) is bonded in a single-bond geometry to one O(2) atom. The H(15)-O(2) bond length is 1.00 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mg(1) and one C(9) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Mg(2), one H(14), and one H(15) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one C(9), and one H(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(15) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Mg(2) and one C(15) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Mg(2) and one C(16) atom. In the seventh O site, O(7) is bonded in a water-like geometry to one C(16) and one H(13) atom. In the eighth O site, O(8) is bonded in a water-like geometry to one C(6) and one H(1) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Mg(2) and one C(6) atom. In the tenth O site, O(10) is bonded in a distorted water-like geometry to one Mg(1), one Mg(2), one H(12), and one H(13) atom. Linkers: 8 Nc1cc(C([O])=O)cc(C(=O)O)c1 ,8 Nc1cc(C([O])=O)cc(C([O])=O)c1. Metal clusters: 4 O.O.O.O.O=[C]O.O=[C]O.[Mg]O[C]O[Mg]O[C]O[Mg].[O][C]=O.[O][C]=O.[O][C]=O.[O][C]=O. RCSR code: bcu. The MOF has largest included sphere 6.81 A, density 0.98 g/cm3, surface area 4491.68 m2/g, accessible volume 0.65 cm3/g