U4P6H6(CO6)3 crystallizes in the monoclinic C2/c space group. There are four inequivalent U sites. In the first U site, U(1) is bonded in a rectangular see-saw-like geometry to one O(10), one O(13), one O(16), and one O(5) atom. The U(1)-O(10) bond length is 2.30 Å. The U(1)-O(13) bond length is 2.26 Å. The U(1)-O(16) bond length is 2.28 Å. The U(1)-O(5) bond length is 2.29 Å. In the second U site, U(2) is bonded to one O(12), one O(14), one O(17), one O(2), one O(6), and one O(7) atom to form distorted UO6 pentagonal pyramids that share  a cornercorner with one P(1)CO3 tetrahedra,  a cornercorner with one P(2)CO3 tetrahedra,  a cornercorner with one P(3)CO3 tetrahedra,  a cornercorner with one P(4)CO3 tetrahedra,  a cornercorner with one P(5)CO3 tetrahedra, and  a cornercorner with one P(6)CO3 tetrahedra. The U(2)-O(12) bond length is 2.32 Å. The U(2)-O(14) bond length is 2.29 Å. The U(2)-O(17) bond length is 2.22 Å. The U(2)-O(2) bond length is 2.33 Å. The U(2)-O(6) bond length is 2.35 Å. The U(2)-O(7) bond length is 2.31 Å. In the third U site, U(3) is bonded in a rectangular see-saw-like geometry to one O(11), one O(18), one O(3), and one O(9) atom. The U(3)-O(11) bond length is 2.27 Å. The U(3)-O(18) bond length is 2.26 Å. The U(3)-O(3) bond length is 2.28 Å. The U(3)-O(9) bond length is 2.32 Å. In the fourth U site, U(4) is bonded in a rectangular see-saw-like geometry to one O(1), one O(15), one O(4), and one O(8) atom. The U(4)-O(1) bond length is 2.32 Å. The U(4)-O(15) bond length is 2.27 Å. The U(4)-O(4) bond length is 2.26 Å. The U(4)-O(8) bond length is 2.30 Å. There are three inequivalent C sites. In the first C site, C(1) is bonded in a distorted tetrahedral geometry to one P(1), one P(4), one H(1), and one H(2) atom. The C(1)-P(1) bond length is 1.80 Å. The C(1)-P(4) bond length is 1.81 Å. The C(1)-H(1) bond length is 0.97 Å. The C(1)-H(2) bond length is 0.97 Å. In the second C site, C(2) is bonded in a distorted water-like geometry to one P(3); one P(5); and two equivalent H(3,4) atoms. The C(2)-P(3) bond length is 1.82 Å. The C(2)-P(5) bond length is 1.79 Å. Both C(2)-H(3,4) bond lengths are 0.97 Å. In the third C site, C(3) is bonded in a distorted water-like geometry to one P(2); one P(6); and two equivalent H(5,6) atoms. The C(3)-P(2) bond length is 1.79 Å. The C(3)-P(6) bond length is 1.79 Å. Both C(3)-H(5,6) bond lengths are 0.97 Å. There are six inequivalent P sites. In the first P site, P(1) is bonded to one C(1), one O(10), one O(6), and one O(8) atom to form PCO3 tetrahedra that share  a cornercorner with one U(2)O6 pentagonal pyramid and  a cornercorner with one P(4)CO3 tetrahedra. The P(1)-O(10) bond length is 1.55 Å. The P(1)-O(6) bond length is 1.52 Å. The P(1)-O(8) bond length is 1.53 Å. In the second P site, P(2) is bonded to one C(3), one O(14), one O(4), and one O(9) atom to form PCO3 tetrahedra that share  a cornercorner with one U(2)O6 pentagonal pyramid and  a cornercorner with one P(6)CO3 tetrahedra. The P(2)-O(14) bond length is 1.53 Å. The P(2)-O(4) bond length is 1.52 Å. The P(2)-O(9) bond length is 1.52 Å. In the third P site, P(3) is bonded to one C(2), one O(1), one O(11), and one O(2) atom to form PCO3 tetrahedra that share  a cornercorner with one U(2)O6 pentagonal pyramid and  a cornercorner with one P(5)CO3 tetrahedra. The P(3)-O(1) bond length is 1.52 Å. The P(3)-O(11) bond length is 1.54 Å. The P(3)-O(2) bond length is 1.52 Å. In the fourth P site, P(4) is bonded to one C(1), one O(13), one O(5), and one O(7) atom to form PCO3 tetrahedra that share  a cornercorner with one U(2)O6 pentagonal pyramid and  a cornercorner with one P(1)CO3 tetrahedra. The P(4)-O(13) bond length is 1.53 Å. The P(4)-O(5) bond length is 1.54 Å. The P(4)-O(7) bond length is 1.52 Å. In the fifth P site, P(5) is bonded to one C(2), one O(12), one O(18), and one O(3) atom to form PCO3 tetrahedra that share  a cornercorner with one U(2)O6 pentagonal pyramid and  a cornercorner with one P(3)CO3 tetrahedra. The P(5)-O(12) bond length is 1.54 Å. The P(5)-O(18) bond length is 1.52 Å. The P(5)-O(3) bond length is 1.53 Å. In the sixth P site, P(6) is bonded to one C(3), one O(15), one O(16), and one O(17) atom to form PCO3 tetrahedra that share  a cornercorner with one U(2)O6 pentagonal pyramid and  a cornercorner with one P(2)CO3 tetrahedra. The P(6)-O(15) bond length is 1.51 Å. The P(6)-O(16) bond length is 1.52 Å. The P(6)-O(17) bond length is 1.53 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(1) atom. In the third H site, H(3,4) is bonded in a single-bond geometry to one C(2) atom. In the fourth H site, H(5,6) is bonded in a single-bond geometry to one C(3) atom. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one U(4) and one P(3) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one U(2) and one P(3) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(5) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one U(4) 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(4) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one U(2) and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one U(2) and one P(4) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one U(4) and one P(1) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one U(3) and one P(2) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one U(1) and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one U(3) and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one U(2) and one P(5) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 150 degrees geometry to one U(1) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one U(2) and one P(2) atom. In the fifteenth O site, O(15) is bonded in a distorted bent 150 degrees geometry to one U(4) and one P(6) atom. In the sixteenth O site, O(16) is bonded in a distorted bent 150 degrees geometry to one U(1) and one P(6) atom. In the seventeenth O site, O(17) is bonded in a distorted linear geometry to one U(2) and one P(6) atom. In the eighteenth O site, O(18) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(5) atom. Linkers: 12 [O]P([O])(=O)CP([O])([O])=O. Metal clusters: 16 [U]. The MOF has largest included sphere 7.30 A, density 2.72 g/cm3, surface area 1581.69 m2/g, accessible volume 0.21 cm3/g