SrP2H12(CO2)4 crystallizes in the tetragonal P-42_1m space group. Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. Both Sr(1)-O(1) bond lengths are 2.54 Å. Both Sr(1)-O(2) bond lengths are 2.69 Å. All Sr(1)-O(3) bond lengths are 2.67 Å. C(1) is bonded to one P(1), one H(2), one H(3), and one O(3) atom to form distorted corner-sharing CPH2O tetrahedra. The C(1)-P(1) bond length is 1.83 Å. The C(1)-H(2) bond length is 1.11 Å. The C(1)-H(3) bond length is 1.10 Å. The C(1)-O(3) bond length is 1.43 Å. P(1) is bonded in a tetrahedral geometry to two equivalent C(1), one O(1), and one O(2) atom. The P(1)-O(1) bond length is 1.52 Å. The P(1)-O(2) bond length is 1.55 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(2) and one O(3) atom. The H(1)-O(2) bond length is 1.66 Å. The H(1)-O(3) bond length is 1.00 Å. 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) is bonded in a single-bond geometry to one C(1) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Sr(1) and one P(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sr(1), one P(1), and two equivalent H(1) atoms. In the third O site, O(3) is bonded in a distorted water-like geometry to one Sr(1), one C(1), and one H(1) atom. Linkers: 4 [O]P(=O)(CO)CO. Metal clusters: 2 [Sr]. The MOF has largest included sphere 1.58 A, density 2.18 g/cm3, surface area 2969.01 m2/g, accessible volume 0.08 cm3/g