Fe3C18O13 crystallizes in the orthorhombic Pnna space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), one O(5), and one O(7) atom. The Fe(1)-O(2) bond length is 2.09 Å. The Fe(1)-O(3) bond length is 1.92 Å. The Fe(1)-O(4) bond length is 1.89 Å. The Fe(1)-O(5) bond length is 2.19 Å. The Fe(1)-O(7) bond length is 2.18 Å. In the second Fe site, Fe(2) is bonded in a square pyramidal geometry to one O(7), two equivalent O(1), and two equivalent O(6) atoms. The Fe(2)-O(7) bond length is 2.08 Å. Both Fe(2)-O(1) bond lengths are 2.02 Å. Both Fe(2)-O(6) bond lengths are 2.20 Å. There are nine inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(1), and one O(2) atom. The C(1)-C(6) bond length is 1.47 Å. The C(1)-O(1) bond length is 1.35 Å. The C(1)-O(2) bond length is 1.30 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(8), one O(3), and one O(4) atom. The C(2)-C(8) bond length is 1.45 Å. The C(2)-O(3) bond length is 1.26 Å. The C(2)-O(4) 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(5), one O(5), and one O(6) atom. The C(3)-C(5) bond length is 1.40 Å. The C(3)-O(5) bond length is 1.27 Å. The C(3)-O(6) bond length is 1.28 Å. In the fourth C site, C(4) is bonded in a bent 120 degrees geometry to one C(4) and one C(5) atom. The C(4)-C(4) bond length is 1.37 Å. The C(4)-C(5) bond length is 1.41 Å. In the fifth C site, C(5) is bonded in a bent 120 degrees geometry to one C(3) and one C(4) atom. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one C(1) and one C(7) atom. The C(6)-C(7) bond length is 1.38 Å. In the seventh C site, C(7) is bonded in a bent 120 degrees geometry to one C(6) and one C(7) atom. The C(7)-C(7) bond length is 1.40 Å. In the eighth C site, C(8) is bonded in a bent 120 degrees geometry to one C(2) and one C(9) atom. The C(8)-C(9) bond length is 1.38 Å. In the ninth C site, C(9) is bonded in a bent 120 degrees geometry to one C(8) and one C(9) atom. The C(9)-C(9) bond length is 1.44 Å. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(2) and two equivalent Fe(1) atoms. In the second O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Fe(2) and one C(1) atom. In the third O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one C(1) atom. In the fourth O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one C(2) atom. In the fifth O site, O(4) is bonded in a water-like geometry to one Fe(1) and one C(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Fe(2) and one C(3) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(1) and one C(3) atom. Linkers: 4 [O]C(=O)[C]/[C]=[C]/[C]C([O])=O ,4 [O][C]([O])/[C]=[C]\[C]=[C]/[C]([O])[O] ,4 [O]C(=O)/[C]=[C]/[C]=[C]/C([O])=O. Metal clusters: 4 [C]1O[Fe]23O[C]O[Fe]45(O1)O[C]O[Fe](O[C]O2)(O[C]O3)(O[C]O4)O5. RCSR code: acs. The MOF has largest included sphere 5.17 A, density 1.34 g/cm3, surface area 3929.38 m2/g, accessible volume 0.40 cm3/g