MgH4(C2O)4 is Indium-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two MgH4(C2O)4 clusters. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(4), one O(5), and one O(6) atom. The Mg(1)-O(1) bond length is 2.03 Å. The Mg(1)-O(4) bond length is 2.05 Å. The Mg(1)-O(5) bond length is 2.21 Å. The Mg(1)-O(6) bond length is 2.16 Å. In the second Mg site, Mg(2) is bonded in an octahedral geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms. Both Mg(2)-O(2) bond lengths are 2.05 Å. Both Mg(2)-O(3) bond lengths are 2.04 Å. Both Mg(2)-O(6) bond lengths are 2.11 Å. There are twelve 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(2) atom. The C(1)-C(2) bond length is 1.53 Å. The C(1)-O(1) bond length is 1.27 Å. The C(1)-O(2) bond length is 1.24 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(7) atom. The C(2)-C(3) bond length is 1.37 Å. The C(2)-C(7) bond length is 1.37 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(2) and one H(1) atom. The C(3)-H(1) bond length is 0.95 Å. In the fourth C site, C(4) is bonded in a distorted single-bond geometry to one C(5) and one H(2) atom. The C(4)-C(5) bond length is 1.38 Å. The C(4)-H(2) bond length is 0.95 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(4), one C(6), and one C(8) atom. The C(5)-C(6) bond length is 1.38 Å. The C(5)-C(8) bond length is 1.53 Å. In the sixth C site, C(6) is bonded in a distorted single-bond geometry to one C(5) and one H(3) atom. The C(6)-H(3) bond length is 0.95 Å. In the seventh C site, C(7) is bonded in a distorted single-bond geometry to one C(2) and one H(4) atom. The C(7)-H(4) bond length is 0.95 Å. In the eighth C site, C(8) is bonded in a distorted bent 120 degrees geometry to one C(5), one O(3), and one O(4) atom. The C(8)-O(3) bond length is 1.26 Å. The C(8)-O(4) bond length is 1.26 Å. In the ninth C site, C(9) is bonded in a distorted bent 120 degrees geometry to one C(10), one O(5), and one O(6) atom. The C(9)-C(10) bond length is 1.51 Å. The C(9)-O(5) bond length is 1.27 Å. The C(9)-O(6) bond length is 1.26 Å. In the tenth C site, C(10) is bonded in a trigonal planar geometry to one C(11), one C(12), and one C(9) atom. The C(10)-C(11) bond length is 1.39 Å. The C(10)-C(12) bond length is 1.41 Å. In the eleventh C site, C(11) is bonded in a distorted single-bond geometry to one C(10) and one H(5) atom. The C(11)-H(5) bond length is 0.95 Å. In the twelfth C site, C(12) is bonded in a distorted single-bond geometry to one C(10) and one H(6) atom. The C(12)-H(6) bond length is 0.95 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(4) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(6) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(7) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(11) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(12) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one C(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Mg(2) and one C(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Mg(2) and one C(8) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Mg(1) and one C(8) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Mg(1) and one C(9) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Mg(2), and one C(9) atom. Linkers: 6 [O]C(=O)c1ccc(C([O])=O)cc1. Metal clusters: 2 O=[C]O[Mg]O[C]O[Mg]O[C]O[Mg]O[C]=O.[O][C]=O.[O][C]=O. RCSR code: hxl. The MOF has largest included sphere 5.86 A, density 0.82 g/cm3, surface area 4625.54 m2/g, accessible volume 0.90 cm3/g