MgC5H5O6 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms. Both Mg(1)-O(1) bond lengths are 2.11 Å. Both Mg(1)-O(2) bond lengths are 2.08 Å. Both Mg(1)-O(5) bond lengths are 2.09 Å. In the second Mg site, Mg(2) is bonded in an octahedral geometry to two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. Both Mg(2)-O(3) bond lengths are 2.05 Å. Both Mg(2)-O(4) bond lengths are 2.04 Å. Both Mg(2)-O(6) bond lengths are 2.14 Å. There are five inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(4) atom. The C(1)-C(2) bond length is 1.50 Å. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(4) bond length is 1.27 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(4) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-C(4) bond length is 1.41 Å. In the third C site, C(3) is bonded in a distorted trigonal planar geometry to one C(2), one C(4), and one H(1) atom. The C(3)-C(4) bond length is 1.40 Å. The C(3)-H(1) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one C(2), one C(3), and one C(5) atom. The C(4)-C(5) bond length is 1.51 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(2), and one O(3) atom. The C(5)-O(2) bond length is 1.26 Å. The C(5)-O(3) bond length is 1.28 Å. There are five inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. The H(2)-O(5) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(5) atom. The H(3)-O(5) bond length is 0.98 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(6) atom. The H(4)-O(6) bond length is 1.00 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(6) atom. The H(5)-O(6) bond length is 0.97 Å. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one H(4), and one H(5) atom. In the second O site, O(1) is bonded in a 2-coordinate geometry to one Mg(1) and one C(1) atom. In the third O site, O(2) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(5) atom. In the fourth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mg(2) and one C(5) atom. In the fifth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(2) and one C(1) atom. In the sixth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one H(2), and one H(3) atom. Linkers: 1 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O. Metal clusters: 2 [Mg]. The MOF has largest included sphere 3.43 A, density 1.53 g/cm3, surface area 3668.60 m2/g, accessible volume 0.20 cm3/g