FeH6(C3O)4 crystallizes in the monoclinic C2/c space group. Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form edge-sharing FeO6 octahedra. Both Fe(1)-O(2) bond lengths are 2.08 Å. There are two shorter (2.09 Å) and two longer (2.20 Å) Fe(1)-O(1) bond lengths. There are six inequivalent C sites. In the first C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(6) atom. The C(2)-C(1) bond length is 1.49 Å. The C(2)-C(3) bond length is 1.42 Å. The C(2)-C(6) bond length is 1.39 Å. In the second 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 1.38 Å. The C(3)-H(1) bond length is 1.09 Å. In the third C site, C(4) is bonded in a distorted single-bond geometry to one C(3), one C(5), and one H(2) atom. The C(4)-C(5) bond length is 1.42 Å. The C(4)-H(2) bond length is 1.09 Å. In the fourth C site, C(5) is bonded in a trigonal planar geometry to one C(4), one C(5), and one C(6) atom. The C(5)-C(5) bond length is 1.44 Å. The C(5)-C(6) bond length is 1.41 Å. In the fifth C site, C(6) is bonded in a distorted single-bond geometry to one C(2), one C(5), and one H(3) atom. The C(6)-H(3) bond length is 1.09 Å. In the sixth 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)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.27 Å. There are three 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. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Fe(1) and one C(1) atom. Linkers: 2 [O]C(=O)c1ccc2cc(C([O])=O)ccc2c1 ,2 [O][C]c1ccc2cc(C([O])=O)ccc2c1. Metal clusters: 2 [Fe]. The MOF has largest included sphere 4.77 A, density 1.62 g/cm3, surface area 3478.07 m2/g, accessible volume 0.20 cm3/g