FeC4HO3 crystallizes in the trigonal R-3 space group. Fe(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form edge-sharing FeO5 square pyramids. The Fe(1)-O(2) bond length is 2.00 Å. There is one shorter (2.24 Å) and one longer (2.25 Å) Fe(1)-O(1) bond length. There is one shorter (2.06 Å) and one longer (2.09 Å) Fe(1)-O(3) bond length. There are four 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 1.66 Å. The C(1)-O(1) bond length is 1.20 Å. The C(1)-O(2) bond length is 1.11 Å. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one C(3), and one C(4) atom. The C(2)-C(3) bond length is 1.38 Å. The C(2)-C(4) bond length is 1.39 Å. In the third C site, C(3) is bonded in a single-bond geometry to one C(2), one C(4), and one O(3) atom. The C(3)-C(4) bond length is 1.47 Å. The C(3)-O(3) bond length is 1.29 Å. In the fourth C site, C(4) is bonded in a 3-coordinate geometry to one C(2), one C(3), and one H(1) atom. The C(4)-H(1) bond length is 1.18 Å. H(1) is bonded in a single-bond geometry to one C(4) atom. There are three 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 distorted bent 120 degrees geometry to one Fe(1) and one C(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one C(3) atom. Linkers: 3 [O]C(=O)c1cc([O])c(C([O])=O)cc1[O]. Metal clusters: 6 [Fe]. The MOF has largest included sphere 11.61 A, density 1.12 g/cm3, surface area 2518.14 m2/g, accessible volume 0.54 cm3/g