MgC7H4O5 crystallizes in the trigonal P3_1 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(13), one O(15), one O(2), and two equivalent O(14) atoms to form distorted corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 63°. The Mg(1)-O(1) bond length is 1.96 Å. The Mg(1)-O(13) bond length is 2.18 Å. The Mg(1)-O(15) bond length is 2.38 Å. The Mg(1)-O(2) bond length is 2.12 Å. There is one shorter (2.03 Å) and one longer (2.06 Å) Mg(1)-O(14) bond length. In the second Mg site, Mg(2) is bonded to one O(3), one O(5), one O(6), one O(7), and two equivalent O(4) atoms to form corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 58°. The Mg(2)-O(3) bond length is 2.22 Å. The Mg(2)-O(5) bond length is 2.25 Å. The Mg(2)-O(6) bond length is 1.99 Å. The Mg(2)-O(7) bond length is 2.08 Å. There is one shorter (2.00 Å) and one longer (2.01 Å) Mg(2)-O(4) bond length. In the third Mg site, Mg(3) is bonded to one O(10), one O(11), one O(12), one O(8), and two equivalent O(9) atoms to form distorted corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 61°. The Mg(3)-O(10) bond length is 2.44 Å. The Mg(3)-O(11) bond length is 2.05 Å. The Mg(3)-O(12) bond length is 2.02 Å. The Mg(3)-O(8) bond length is 2.28 Å. There is one shorter (1.97 Å) and one longer (1.99 Å) Mg(3)-O(9) bond length. There are twenty-one inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(2), one C(6), and one C(7) atom. The C(1)-C(2) bond length is 1.41 Å. The C(1)-C(6) bond length is 1.41 Å. The C(1)-C(7) bond length is 1.48 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to one C(1) and one H(1) atom. The C(2)-H(1) bond length is 1.09 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one O(3) atom. The C(3)-O(3) bond length is 1.38 Å. In the fourth C site, C(4) is bonded in a distorted single-bond geometry to one O(4) atom. The C(4)-O(4) bond length is 1.33 Å. In the fifth C site, C(5) is bonded in a distorted single-bond geometry to one C(6) and one O(5) atom. The C(5)-C(6) bond length is 1.38 Å. The C(5)-O(5) bond length is 1.39 Å. In the sixth C site, C(6) is bonded in a distorted trigonal planar geometry to one C(1), one C(5), and one H(2) atom. The C(6)-H(2) bond length is 1.09 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(1), and one O(2) atom. The C(7)-O(1) bond length is 1.27 Å. The C(7)-O(2) bond length is 1.29 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(13), one C(14), and one C(9) atom. The C(8)-C(13) bond length is 1.41 Å. The C(8)-C(14) bond length is 1.48 Å. The C(8)-C(9) bond length is 1.41 Å. In the ninth C site, C(9) is bonded in a distorted trigonal planar geometry to one C(10), one C(8), and one H(5) atom. The C(9)-C(10) bond length is 1.38 Å. The C(9)-H(5) bond length is 1.09 Å. In the tenth C site, C(10) is bonded in a distorted single-bond geometry to one C(9) and one O(8) atom. The C(10)-O(8) bond length is 1.39 Å. In the eleventh C site, C(11) is bonded in a distorted single-bond geometry to one O(9) atom. The C(11)-O(9) bond length is 1.33 Å. In the twelfth C site, C(12) is bonded in a distorted single-bond geometry to one O(10) atom. The C(12)-O(10) bond length is 1.38 Å. In the thirteenth C site, C(13) is bonded in a distorted single-bond geometry to one C(8) and one H(6) atom. The C(13)-H(6) bond length is 1.09 Å. In the fourteenth C site, C(14) is bonded in a bent 120 degrees geometry to one C(8), one O(6), and one O(7) atom. The C(14)-O(6) bond length is 1.27 Å. The C(14)-O(7) bond length is 1.29 Å. In the fifteenth C site, C(15) is bonded in a trigonal planar geometry to one C(16), one C(20), and one C(21) atom. The C(15)-C(16) bond length is 1.41 Å. The C(15)-C(20) bond length is 1.41 Å. The C(15)-C(21) bond length is 1.49 Å. In the sixteenth C site, C(16) is bonded in a distorted trigonal planar geometry to one C(15), one C(17), and one H(9) atom. The C(16)-C(17) bond length is 1.39 Å. The C(16)-H(9) bond length is 1.09 Å. In the seventeenth C site, C(17) is bonded in a distorted single-bond geometry to one C(16) and one O(13) atom. The C(17)-O(13) bond length is 1.38 Å. In the eighteenth C site, C(18) is bonded in a distorted single-bond geometry to one O(14) atom. The C(18)-O(14) bond length is 1.33 Å. In the nineteenth C site, C(19) is bonded in a distorted single-bond geometry to one O(15) atom. The C(19)-O(15) bond length is 1.39 Å. In the twentieth C site, C(20) is bonded in a distorted single-bond geometry to one C(15) and one H(10) atom. The C(20)-H(10) bond length is 1.09 Å. In the twenty-first C site, C(21) is bonded in a bent 120 degrees geometry to one C(15), one O(11), and one O(12) atom. The C(21)-O(11) bond length is 1.27 Å. The C(21)-O(12) bond length is 1.29 Å. There are twelve inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(6) atom. In the third H site, H(3) is bonded in a distorted single-bond geometry to one O(3) and one O(7) atom. The H(3)-O(3) bond length is 1.01 Å. The H(3)-O(7) bond length is 1.66 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(5) atom. The H(4)-O(5) bond length is 0.97 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(9) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(13) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(8) atom. The H(7)-O(8) bond length is 0.98 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(10) atom. The H(8)-O(10) bond length is 0.97 Å. In the ninth H site, H(9) is bonded in a single-bond geometry to one C(16) atom. In the tenth H site, H(10) is bonded in a single-bond geometry to one C(20) atom. In the eleventh H site, H(11) is bonded in a distorted single-bond geometry to one O(13) and one O(2) atom. The H(11)-O(13) bond length is 1.01 Å. The H(11)-O(2) bond length is 1.66 Å. In the twelfth H site, H(12) is bonded in a single-bond geometry to one O(15) atom. The H(12)-O(15) bond length is 0.97 Å. There are fifteen inequivalent O sites. In the first O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Mg(3), one C(10), and one H(7) atom. In the second O site, O(9) is bonded in a trigonal planar geometry to two equivalent Mg(3) and one C(11) atom. In the third O site, O(10) is bonded in a 3-coordinate geometry to one Mg(3), one C(12), and one H(8) atom. In the fourth O site, O(11) is bonded in a bent 120 degrees geometry to one Mg(3) and one C(21) atom. In the fifth O site, O(12) is bonded in a bent 120 degrees geometry to one Mg(3) and one C(21) atom. In the sixth O site, O(13) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one C(17), and one H(11) atom. In the seventh O site, O(14) is bonded in a trigonal planar geometry to two equivalent Mg(1) and one C(18) atom. In the eighth O site, O(15) is bonded in a 3-coordinate geometry to one Mg(1), one C(19), and one H(12) atom. In the ninth O site, O(1) is bonded in a bent 150 degrees geometry to one Mg(1) and one C(7) atom. In the tenth O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one C(7), and one H(11) atom. In the eleventh O site, O(3) is bonded in a 3-coordinate geometry to one Mg(2), one C(3), and one H(3) atom. In the twelfth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Mg(2) and one C(4) atom. In the thirteenth O site, O(5) is bonded in a 3-coordinate geometry to one Mg(2), one C(5), and one H(4) atom. In the fourteenth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(2) and one C(14) atom. In the fifteenth O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(2), one C(14), and one H(3) atom. Linkers: 9 [O]C(=O)c1cc(O)c([O])c(O)c1. Metal clusters: 9 [Mg]. The MOF has largest included sphere 3.39 A, density 1.42 g/cm3, surface area 3632.16 m2/g, accessible volume 0.25 cm3/g