FePO7 crystallizes in the orthorhombic Pccn space group. Fe(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Fe(1)-O(1) bond length is 1.98 Å. The Fe(1)-O(2) bond length is 1.97 Å. The Fe(1)-O(3) bond length is 1.96 Å. The Fe(1)-O(4) bond length is 2.06 Å. The Fe(1)-O(5) bond length is 1.87 Å. The Fe(1)-O(6) bond length is 1.84 Å. The Fe(1)-O(7) bond length is 2.08 Å. P(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The P(1)-O(1) bond length is 1.51 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.55 Å. The P(1)-O(4) bond length is 1.48 Å. The P(1)-O(5) bond length is 1.55 Å. The P(1)-O(6) bond length is 1.56 Å. The P(1)-O(7) bond length is 1.43 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(1), one P(1), and one O(3) atom. The O(2)-O(3) bond length is 1.32 Å. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Fe(1), one P(1), and one O(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Fe(1), one P(1), and one O(5) atom. The O(4)-O(5) bond length is 1.04 Å. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Fe(1), one P(1), and one O(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Fe(1), one P(1), and one O(7) atom. The O(6)-O(7) bond length is 1.06 Å. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Fe(1), one P(1), and one O(6) atom. Linkers: 4 [O]OP1([O])(O[O])OO1 ,4 [O]O[P](=O)O[O].[O][O]. Metal clusters: 8 [Fe]. The MOF has largest included sphere 3.79 A, density 2.69 g/cm3, surface area 1746.81 m2/g, accessible volume 0.15 cm3/g