Mg2PH(CO3)4 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(5), one O(6), one O(7), and one O(8) atom to form MgO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra. The Mg(1)-O(1) bond length is 1.99 Å. The Mg(1)-O(5) bond length is 2.11 Å. The Mg(1)-O(6) bond length is 2.13 Å. The Mg(1)-O(7) bond length is 2.12 Å. The Mg(1)-O(8) bond length is 2.10 Å. In the second Mg site, Mg(2) is bonded to one O(10), one O(11), one O(12), one O(2), and one O(9) atom to form MgO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra. The Mg(2)-O(10) bond length is 2.10 Å. The Mg(2)-O(11) bond length is 2.07 Å. The Mg(2)-O(12) bond length is 2.11 Å. The Mg(2)-O(2) bond length is 2.01 Å. The Mg(2)-O(9) bond length is 2.14 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(1)-O(5) bond length is 1.25 Å. The C(1)-O(6) bond length is 1.24 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(7) and one O(8) atom. The C(2)-O(7) bond length is 1.24 Å. The C(2)-O(8) bond length is 1.26 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one O(10) and one O(9) atom. The C(3)-O(10) bond length is 1.25 Å. The C(3)-O(9) bond length is 1.24 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(11) and one O(12) atom. The C(4)-O(11) bond length is 1.26 Å. The C(4)-O(12) bond length is 1.24 Å. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O5 square pyramid and  a cornercorner with one Mg(2)O5 square pyramid. The P(1)-O(1) bond length is 1.51 Å. The P(1)-O(2) bond length is 1.50 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.59 Å. H(1) is bonded in a single-bond geometry to one O(4) atom. The H(1)-O(4) bond length is 0.82 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mg(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Mg(2) and one P(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to one P(1) atom. In the fourth O site, O(4) is bonded in a water-like geometry to one P(1) and one H(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(2) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Mg(1) and one C(2) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Mg(2) and one C(3) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Mg(2) and one C(3) atom. In the eleventh O site, O(11) is bonded in a distorted bent 120 degrees geometry to one Mg(2) and one C(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Mg(2) and one C(4) atom. Linkers: 3 [O]C(=O)C([O])=O. Metal clusters: 4 [Mg]. The MOF has largest included sphere 5.89 A, density 0.92 g/cm3, surface area 4273.28 m2/g, accessible volume 0.74 cm3/g