SrC2PH9O9 crystallizes in the monoclinic P2_1/c space group. Sr(1) is bonded in a 8-coordinate geometry to one O(1), one O(4), one O(6), one O(7), one O(8), one O(9), and two equivalent O(5) atoms. The Sr(1)-O(1) bond length is 2.60 Å. The Sr(1)-O(4) bond length is 2.52 Å. The Sr(1)-O(6) bond length is 2.65 Å. The Sr(1)-O(7) bond length is 2.53 Å. The Sr(1)-O(8) bond length is 2.54 Å. The Sr(1)-O(9) bond length is 2.64 Å. There is one shorter (2.66 Å) and one longer (2.75 Å) Sr(1)-O(5) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded in a 4-coordinate geometry to one C(2), one P(1), one H(1), and one O(1) atom. The C(1)-C(2) bond length is 1.53 Å. The C(1)-P(1) bond length is 1.85 Å. The C(1)-H(1) bond length is 1.10 Å. The C(1)-O(1) bond length is 1.43 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(5), and one O(6) atom. The C(2)-O(5) bond length is 1.26 Å. The C(2)-O(6) bond length is 1.28 Å. P(1) is bonded in a distorted tetrahedral geometry to one C(1), one O(2), one O(3), and one O(4) atom. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.59 Å. The P(1)-O(4) bond length is 1.50 Å. There are nine 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 O(1) atom. The H(2)-O(1) bond length is 0.98 Å. In the third H site, H(3) is bonded in a linear geometry to one O(2) and one O(3) atom. The H(3)-O(2) bond length is 1.52 Å. The H(3)-O(3) bond length is 1.03 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(7) atom. The H(4)-O(7) bond length is 0.99 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(8) atom. The H(5)-O(8) bond length is 1.00 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(9) atom. The H(6)-O(9) bond length is 0.97 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(8) atom. The H(7)-O(8) bond length is 0.99 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(9) atom. The H(8)-O(9) bond length is 0.99 Å. In the ninth H site, H(9) is bonded in a single-bond geometry to one O(7) atom. The H(9)-O(7) bond length is 0.98 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Sr(1), one C(1), and one H(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one P(1) and one H(3) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one H(3) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Sr(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to two equivalent Sr(1) and one C(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Sr(1) and one C(2) atom. In the seventh O site, O(7) is bonded in a distorted water-like geometry to one Sr(1), one H(4), and one H(9) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Sr(1), one H(5), and one H(7) atom. In the ninth O site, O(9) is bonded in a water-like geometry to one Sr(1), one H(6), and one H(8) atom. Linkers: 2 [O]C(=O)[C@@H](O)P([O])(=O)O ,2 [O]C(=O)[C@H](O)P([O])(=O)O. Metal clusters: 4 [Sr]. The MOF has largest included sphere 2.49 A, density 2.04 g/cm3, surface area 3124.23 m2/g, accessible volume 0.09 cm3/g