FeC4HO3CO2 crystallizes in the triclinic P1 space group. The structure consists of six carbon dioxide molecules inside a FeC4HO3 framework. In the FeC4HO3 framework, there are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(1), one O(13), one O(14), one O(3), and one O(8) atom. The Fe(1)-O(1) bond length is 2.02 Å. The Fe(1)-O(13) bond length is 2.03 Å. The Fe(1)-O(14) bond length is 2.10 Å. The Fe(1)-O(3) bond length is 2.08 Å. The Fe(1)-O(8) bond length is 2.07 Å. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(1), one O(14), one O(15), one O(2), and one O(9) atom. The Fe(2)-O(1) bond length is 2.08 Å. The Fe(2)-O(14) bond length is 2.02 Å. The Fe(2)-O(15) bond length is 2.10 Å. The Fe(2)-O(2) bond length is 2.02 Å. The Fe(2)-O(9) bond length is 2.07 Å. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(13), one O(15), one O(2), one O(3), and one O(7) atom. The Fe(3)-O(13) bond length is 2.10 Å. The Fe(3)-O(15) bond length is 2.02 Å. The Fe(3)-O(2) bond length is 2.08 Å. The Fe(3)-O(3) bond length is 2.02 Å. The Fe(3)-O(7) bond length is 2.07 Å. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one O(11), one O(16), one O(17), one O(4), and one O(6) atom. The Fe(4)-O(11) bond length is 2.07 Å. The Fe(4)-O(16) bond length is 2.03 Å. The Fe(4)-O(17) bond length is 2.10 Å. The Fe(4)-O(4) bond length is 2.02 Å. The Fe(4)-O(6) bond length is 2.08 Å. In the fifth Fe site, Fe(5) is bonded in a 5-coordinate geometry to one O(12), one O(17), one O(18), one O(4), and one O(5) atom. The Fe(5)-O(12) bond length is 2.07 Å. The Fe(5)-O(17) bond length is 2.02 Å. The Fe(5)-O(18) bond length is 2.10 Å. The Fe(5)-O(4) bond length is 2.08 Å. The Fe(5)-O(5) bond length is 2.02 Å. In the sixth Fe site, Fe(6) is bonded in a 5-coordinate geometry to one O(10), one O(16), one O(18), one O(5), and one O(6) atom. The Fe(6)-O(10) bond length is 2.07 Å. The Fe(6)-O(16) bond length is 2.10 Å. The Fe(6)-O(18) bond length is 2.02 Å. The Fe(6)-O(5) bond length is 2.08 Å. The Fe(6)-O(6) bond length is 2.02 Å. There are twenty-one inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(7,10); one O(1); and one O(7) atom. The C(1)-C(7,10) bond length is 1.47 Å. The C(1)-O(1) bond length is 1.30 Å. The C(1)-O(7) bond length is 1.27 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(8), one O(2), and one O(8) atom. The C(2)-C(8) bond length is 1.47 Å. The C(2)-O(2) bond length is 1.30 Å. The C(2)-O(8) bond length is 1.27 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(9), one O(3), and one O(9) atom. The C(3)-C(9) bond length is 1.47 Å. The C(3)-O(3) bond length is 1.30 Å. The C(3)-O(9) bond length is 1.27 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(7,10); one O(10); and one O(4) atom. The C(4)-C(7,10) bond length is 1.47 Å. The C(4)-O(10) bond length is 1.27 Å. The C(4)-O(4) bond length is 1.30 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(11), one O(11), and one O(5) atom. The C(5)-C(11) bond length is 1.47 Å. The C(5)-O(11) bond length is 1.27 Å. The C(5)-O(5) bond length is 1.30 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one C(12), one O(12), and one O(6) atom. The C(6)-C(12) bond length is 1.47 Å. The C(6)-O(12) bond length is 1.27 Å. The C(6)-O(6) bond length is 1.30 Å. In the seventh C site, C(7,10) is bonded in a trigonal planar geometry to one C(1), one C(13), and one C(22) atom. The C(7,10)-C(13) bond length is 1.44 Å. The C(7,10)-C(22) bond length is 1.40 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(14), one C(2), and one C(23) atom. The C(8)-C(14) bond length is 1.44 Å. The C(8)-C(23) bond length is 1.40 Å. In the ninth C site, C(9) is bonded in a trigonal planar geometry to one C(15,18); one C(21,24); and one C(3) atom. The C(9)-C(15,18) bond length is 1.44 Å. The C(9)-C(21,24) bond length is 1.40 Å. In the tenth C site, C(11) is bonded in a trigonal planar geometry to one C(17), one C(20), and one C(5) atom. The C(11)-C(17) bond length is 1.44 Å. The C(11)-C(20) bond length is 1.40 Å. In the eleventh C site, C(12) is bonded in a trigonal planar geometry to one C(15,18); one C(21,24); and one C(6) atom. The C(12)-C(15,18) bond length is 1.44 Å. The C(12)-C(21,24) bond length is 1.40 Å. In the twelfth C site, C(13) is bonded in a distorted single-bond geometry to one C(19); one C(7,10); and one O(13) atom. The C(13)-C(19) bond length is 1.40 Å. The C(13)-O(13) bond length is 1.34 Å. In the thirteenth C site, C(14) is bonded in a distorted single-bond geometry to one C(20), one C(8), and one O(14) atom. The C(14)-C(20) bond length is 1.40 Å. The C(14)-O(14) bond length is 1.34 Å. In the fourteenth C site, C(15,18) is bonded in a distorted single-bond geometry to one C(21,24); one C(9); and one O(15) atom. The C(15,18)-C(21,24) bond length is 1.40 Å. The C(15,18)-O(15) bond length is 1.34 Å. In the fifteenth C site, C(16) is bonded in a distorted single-bond geometry to one C(22); one C(7,10); and one O(16) atom. The C(16)-C(22) bond length is 1.40 Å. The C(16)-C(7,10) bond length is 1.44 Å. The C(16)-O(16) bond length is 1.34 Å. In the sixteenth C site, C(17) is bonded in a distorted single-bond geometry to one C(11), one C(23), and one O(17) atom. The C(17)-C(23) bond length is 1.40 Å. The C(17)-O(17) bond length is 1.34 Å. In the seventeenth C site, C(19) is bonded in a distorted trigonal planar geometry to one C(13); one C(7,10); and one H(1,4) atom. The C(19)-C(7,10) bond length is 1.40 Å. The C(19)-H(1,4) bond length is 1.09 Å. In the eighteenth C site, C(20) is bonded in a distorted trigonal planar geometry to one C(11); one C(14); and one H(2,5) atom. The C(20)-H(2,5) bond length is 1.09 Å. In the nineteenth C site, C(21,24) is bonded in a distorted trigonal planar geometry to one C(12); one C(15,18); and one H(3,6) atom. The C(21,24)-H(3,6) bond length is 1.09 Å. In the twentieth C site, C(22) is bonded in a distorted trigonal planar geometry to one C(16); one C(7,10); and one H(1,4) atom. The C(22)-H(1,4) bond length is 1.09 Å. In the twenty-first C site, C(23) is bonded in a distorted trigonal planar geometry to one C(17); one C(8); and one H(2,5) atom. The C(23)-H(2,5) bond length is 1.09 Å. There are three inequivalent H sites. In the first H site, H(1,4) is bonded in a single-bond geometry to one C(19) atom. In the second H site, H(2,5) is bonded in a single-bond geometry to one C(20) atom. In the third H site, H(3,6) is bonded in a single-bond geometry to one C(21,24) atom. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one C(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(2), one Fe(3), and one C(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one C(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Fe(4), one Fe(5), and one C(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Fe(5), one Fe(6), and one C(5) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Fe(4), one Fe(6), and one C(6) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Fe(3) and one C(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Fe(1) and one C(2) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Fe(2) and one C(3) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Fe(6) and one C(4) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Fe(4) and one C(5) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Fe(5) and one C(6) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(3), and one C(13) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one C(14) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Fe(2); one Fe(3); and one C(15,18) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Fe(4), one Fe(6), and one C(16) atom. In the seventeenth O site, O(17) is bonded in a 3-coordinate geometry to one Fe(4), one Fe(5), and one C(17) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Fe(5); one Fe(6); and one C(15,18) atom. The O(18)-C(15,18) bond length is 1.34 Å. Linkers: 3 [O]C(=O)c1cc([O])c(C([O])=O)cc1[O]. Metal clusters: 6 [Fe]. The MOF has largest included sphere 7.00 A, density 1.48 g/cm3, surface area 2976.04 m2/g, accessible volume 0.35 cm3/g