MgH6(C2O3)2 crystallizes in the orthorhombic P2_12_12_1 space group. Mg(1) is bonded in an octahedral geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Mg(1)-O(1) bond length is 2.15 Å. The Mg(1)-O(2) bond length is 2.04 Å. The Mg(1)-O(3) bond length is 2.15 Å. The Mg(1)-O(4) bond length is 2.09 Å. The Mg(1)-O(5) bond length is 2.13 Å. The Mg(1)-O(6) bond length is 2.13 Å. There are four inequivalent C sites. In the first C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(2)-O(3) bond length is 1.26 Å. The C(2)-O(4) bond length is 1.28 Å. In the second C site, C(3) is bonded in a distorted trigonal non-coplanar geometry to one H(1), one H(2), and one O(1) atom. The C(3)-H(1) bond length is 1.10 Å. The C(3)-H(2) bond length is 1.10 Å. The C(3)-O(1) bond length is 1.43 Å. In the third C site, C(4) is bonded in a distorted trigonal non-coplanar geometry to one H(3), one H(5), and one O(1) atom. The C(4)-H(3) bond length is 1.10 Å. The C(4)-H(5) bond length is 1.10 Å. The C(4)-O(1) bond length is 1.44 Å. In the fourth C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(2) and one O(5) atom. The C(1)-O(2) bond length is 1.28 Å. The C(1)-O(5) bond length is 1.26 Å. There are six 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 C(3) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(4) atom. 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 0.98 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(4) atom. 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. There are six inequivalent O sites. In the first O site, O(6) is bonded in a distorted water-like geometry to one Mg(1), one H(4), and one H(6) atom. In the second O site, O(1) is bonded in a trigonal non-coplanar geometry to one Mg(1), one C(3), and one C(4) atom. In the third O site, O(5) is bonded in a water-like geometry to one Mg(1) and one C(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one C(1) atom. In the fifth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one C(2) atom. In the sixth O site, O(4) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(2) atom. Linkers: 4 [O]C(=O)COCC([O])=O. Metal clusters: 4 [Mg]. The MOF has largest included sphere 1.64 A, density 1.85 g/cm3, surface area 3477.49 m2/g, accessible volume 0.07 cm3/g