In4P7H9O28 crystallizes in the trigonal P-3c1 space group. There are three inequivalent In sites. In the first In site, In(1) is bonded to one O(3), one O(5), one O(6), one O(8), and one O(9) atom to form InO5 square pyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The In(1)-O(3) bond length is 2.13 Å. The In(1)-O(5) bond length is 2.15 Å. The In(1)-O(6) bond length is 2.12 Å. The In(1)-O(8) bond length is 2.09 Å. The In(1)-O(9) bond length is 2.10 Å. In the second In site, In(2) is bonded to six equivalent O(1) atoms to form InO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. All In(2)-O(1) bond lengths are 2.14 Å. In the third In site, In(3) is bonded to six equivalent O(2) atoms to form InO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. All In(3)-O(2) bond lengths are 2.09 Å. There are three inequivalent P sites. In the first P site, 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 In(2)O6 octahedra,  a cornercorner with one In(3)O6 octahedra, and  a cornercorner with one In(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 26-45°. The P(1)-O(1) bond length is 1.48 Å. The P(1)-O(2) bond length is 1.44 Å. The P(1)-O(3) bond length is 1.52 Å. The P(1)-O(4) bond length is 1.56 Å. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share corners with three equivalent In(1)O5 square pyramids. The P(2)-O(5) bond length is 1.51 Å. The P(2)-O(6) bond length is 1.51 Å. The P(2)-O(7) bond length is 1.60 Å. The P(2)-O(8) bond length is 1.50 Å. In the third P site, P(3) is bonded to one O(10) and three equivalent O(9) atoms to form PO4 tetrahedra that share corners with three equivalent In(1)O5 square pyramids. The P(3)-O(10) bond length is 1.58 Å. All P(3)-O(9) bond lengths are 1.50 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(4) atom. The H(1)-O(4) bond length is 0.96 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(7) atom. The H(2)-O(7) bond length is 0.96 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(10) atom. The H(3)-O(10) bond length is 0.85 Å. There are ten inequivalent O sites. In the first O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one P(3) and three equivalent H(3) atoms. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to one In(2) and one P(1) atom. In the third O site, O(2) is bonded in a bent 150 degrees geometry to one In(3) and one P(1) atom. In the fourth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one In(1) and one P(1) atom. In the fifth O site, O(4) is bonded in a water-like geometry to one P(1) and one H(1) atom. In the sixth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one In(1) and one P(2) atom. In the seventh O site, O(6) is bonded in a distorted bent 150 degrees geometry to one In(1) and one P(2) atom. In the eighth O site, O(7) is bonded in a water-like geometry to one P(2) and one H(2) atom. In the ninth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one In(1) and one P(2) atom. In the tenth O site, O(9) is bonded in a bent 150 degrees geometry to one In(1) and one P(3) atom. Linkers: 24 [O]P([O])(=O)O ,4 O.[H].[O]P([O])[O]. Metal clusters: 16 [In]. The MOF has largest included sphere 4.92 A, density 2.39 g/cm3, surface area 2341.25 m2/g, accessible volume 0.13 cm3/g