YbCPH3O6 crystallizes in the triclinic P-1 space group. Yb(1) is bonded in a 8-coordinate geometry to one O(2), one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(3) atoms. The Yb(1)-O(2) bond length is 2.17 Å. The Yb(1)-O(4) bond length is 2.39 Å. The Yb(1)-O(5) bond length is 2.40 Å. The Yb(1)-O(6) bond length is 2.29 Å. There is one shorter (2.33 Å) and one longer (2.37 Å) Yb(1)-O(1) bond length. There is one shorter (2.31 Å) and one longer (2.40 Å) Yb(1)-O(3) bond length. C(1) is bonded in a distorted bent 120 degrees geometry to one O(4) and one O(5) atom. The C(1)-O(4) bond length is 1.26 Å. The C(1)-O(5) bond length is 1.26 Å. P(1) is bonded in a distorted tetrahedral geometry to one H(1), one O(1), one O(2), and one O(3) atom. The P(1)-H(1) bond length is 1.41 Å. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(2) bond length is 1.52 Å. The P(1)-O(3) bond length is 1.55 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one P(1) atom. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(5) and one O(6) atom. The H(2)-O(5) bond length is 1.72 Å. The H(2)-O(6) bond length is 0.99 Å. In the third H site, H(3) is bonded in a distorted single-bond geometry to one O(4) and one O(6) atom. The H(3)-O(4) bond length is 1.70 Å. The H(3)-O(6) bond length is 0.99 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Yb(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Yb(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Yb(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Yb(1), one C(1), and one H(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Yb(1), one C(1), and one H(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Yb(1), one H(2), and one H(3) atom. Linkers: 1 [O]C(=O)C([O])=O ,2 [O][PH]([O])=O. Metal clusters: 2 [Yb]. The MOF has largest included sphere 3.14 A, density 3.36 g/cm3, surface area 1497.12 m2/g, accessible volume 0.09 cm3/g