U5(PO4)4 crystallizes in the orthorhombic Cmc2_1 space group. There are three inequivalent U sites. In the first U site, U(1) is bonded in a distorted pentagonal planar geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The U(1)-O(1) bond length is 2.40 Å. The U(1)-O(2) bond length is 2.47 Å. The U(1)-O(3) bond length is 2.50 Å. The U(1)-O(4) bond length is 2.41 Å. The U(1)-O(5) bond length is 2.28 Å. In the second U site, U(2) is bonded in a distorted pentagonal planar geometry to one O(1), one O(2), one O(3), one O(4), and one O(6) atom. The U(2)-O(1) bond length is 2.52 Å. The U(2)-O(2) bond length is 2.36 Å. The U(2)-O(3) bond length is 2.36 Å. The U(2)-O(4) bond length is 2.52 Å. The U(2)-O(6) bond length is 2.26 Å. In the third U site, U(3) is bonded in a 4-coordinate geometry to two equivalent O(7) and two equivalent O(8) atoms. Both U(3)-O(7) bond lengths are 2.35 Å. Both U(3)-O(8) bond lengths are 2.33 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded in a tetrahedral geometry to one O(2), one O(3), one O(5), and one O(8) atom. 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(5) bond length is 1.51 Å. The P(1)-O(8) bond length is 1.49 Å. In the second P site, P(2) is bonded in a tetrahedral geometry to one O(1), one O(4), one O(6), and one O(7) atom. The P(2)-O(1) bond length is 1.54 Å. The P(2)-O(4) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.55 Å. The P(2)-O(7) bond length is 1.51 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one U(1), one U(2), and one P(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one U(1), one U(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one U(1), one U(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one U(1), one U(2), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one U(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one U(2) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one U(3) and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one U(3) and one P(1) atom. Linkers: 16 [O]P([O])([O])=O. Metal clusters: 20 [U]. The MOF has largest included sphere 5.88 A, density 3.70 g/cm3, surface area 1176.80 m2/g, accessible volume 0.13 cm3/g