Fe4O(PO4)4 crystallizes in the monoclinic C2 space group. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(2), one O(22), one O(24), one O(25), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(6)O4 tetrahedra,  a cornercorner with one Fe(2)O5 trigonal bipyramid,  an edgeedge with one P(3)O4 tetrahedra, and  an edgeedge with one Fe(4)O5 trigonal bipyramid. The Fe(1)-O(10) bond length is 2.16 Å. The Fe(1)-O(2) bond length is 1.99 Å. The Fe(1)-O(22) bond length is 1.98 Å. The Fe(1)-O(24) bond length is 2.01 Å. The Fe(1)-O(25) bond length is 1.99 Å. The Fe(1)-O(9) bond length is 2.16 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(13), one O(21), one O(25), and one O(4) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and  a cornercorner with one Fe(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 55°. The Fe(2)-O(1) bond length is 1.93 Å. The Fe(2)-O(13) bond length is 1.98 Å. The Fe(2)-O(21) bond length is 1.93 Å. The Fe(2)-O(25) bond length is 1.90 Å. The Fe(2)-O(4) bond length is 2.02 Å. In the third Fe site, Fe(3) is bonded to one O(14), one O(17), one O(26), one O(5), and one O(6) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and corners with two equivalent Fe(5)O5 trigonal bipyramids. The Fe(3)-O(14) bond length is 2.03 Å. The Fe(3)-O(17) bond length is 1.89 Å. The Fe(3)-O(26) bond length is 1.95 Å. The Fe(3)-O(5) bond length is 1.94 Å. The Fe(3)-O(6) bond length is 1.90 Å. In the fourth Fe site, Fe(4) is bonded to one O(15), one O(23), one O(25), one O(7), and one O(9) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O6 octahedra. The Fe(4)-O(15) bond length is 1.97 Å. The Fe(4)-O(23) bond length is 2.01 Å. The Fe(4)-O(25) bond length is 2.18 Å. The Fe(4)-O(7) bond length is 2.05 Å. The Fe(4)-O(9) bond length is 2.08 Å. In the fifth Fe site, Fe(5) is bonded to one O(12), one O(18), one O(20), one O(26), and one O(8) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(5)O4 tetrahedra,  a cornercorner with one Fe(5)O5 trigonal bipyramid, and corners with two equivalent Fe(3)O5 trigonal bipyramids. The Fe(5)-O(12) bond length is 2.13 Å. The Fe(5)-O(18) bond length is 1.98 Å. The Fe(5)-O(20) bond length is 2.02 Å. The Fe(5)-O(26) bond length is 2.39 Å. The Fe(5)-O(8) bond length is 2.02 Å. In the sixth Fe site, Fe(6) is bonded in a 5-coordinate geometry to one O(10), one O(16), one O(19), one O(25), and one O(3) atom. The Fe(6)-O(10) bond length is 2.11 Å. The Fe(6)-O(16) bond length is 2.01 Å. The Fe(6)-O(19) bond length is 2.04 Å. The Fe(6)-O(25) bond length is 2.27 Å. The Fe(6)-O(3) bond length is 2.07 Å. There are six 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 Fe(1)O6 octahedra and corners with two equivalent Fe(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 56°. The P(1)-O(1) bond length is 1.57 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.51 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  a cornercorner with one Fe(4)O5 trigonal bipyramid,  a cornercorner with one Fe(5)O5 trigonal bipyramid, and corners with two equivalent Fe(3)O5 trigonal bipyramids. The P(2)-O(5) bond length is 1.57 Å. The P(2)-O(6) bond length is 1.55 Å. The P(2)-O(7) bond length is 1.50 Å. The P(2)-O(8) bond length is 1.54 Å. In the third P site, P(3) is bonded to one O(10), one O(11), one O(12), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(4)O5 trigonal bipyramid,  a cornercorner with one Fe(5)O5 trigonal bipyramid, and  an edgeedge with one Fe(1)O6 octahedra. The P(3)-O(10) bond length is 1.58 Å. The P(3)-O(11) bond length is 1.50 Å. The P(3)-O(12) bond length is 1.51 Å. The P(3)-O(9) bond length is 1.59 Å. In the fourth P site, P(4) is bonded to one O(13), one O(14), one O(15), and one O(16) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O5 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid, and  a cornercorner with one Fe(4)O5 trigonal bipyramid. The P(4)-O(13) bond length is 1.56 Å. The P(4)-O(14) bond length is 1.51 Å. The P(4)-O(15) bond length is 1.54 Å. The P(4)-O(16) bond length is 1.54 Å. In the fifth P site, P(5) is bonded to one O(17), one O(18), one O(19), and one O(20) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(3)O5 trigonal bipyramid and corners with two equivalent Fe(5)O5 trigonal bipyramids. The P(5)-O(17) bond length is 1.56 Å. The P(5)-O(18) bond length is 1.54 Å. The P(5)-O(19) bond length is 1.51 Å. The P(5)-O(20) bond length is 1.53 Å. In the sixth P site, P(6) is bonded to one O(21), one O(22), one O(23), and one O(24) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O5 trigonal bipyramid, and  a cornercorner with one Fe(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 34-55°. The P(6)-O(21) bond length is 1.57 Å. The P(6)-O(22) bond length is 1.56 Å. The P(6)-O(23) bond length is 1.47 Å. The P(6)-O(24) bond length is 1.52 Å. There are twenty-six inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Fe(2) and one P(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Fe(6) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to one Fe(2) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Fe(3) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Fe(3) and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(4) and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Fe(5) and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Fe(1), one Fe(4), and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Fe(1), one Fe(6), and one P(3) atom. In the eleventh O site, O(11) is bonded in a single-bond geometry to one P(3) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Fe(5) and one P(3) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one Fe(2) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to one Fe(3) and one P(4) atom. In the fifteenth O site, O(15) is bonded in a bent 120 degrees geometry to one Fe(4) and one P(4) atom. In the sixteenth O site, O(16) is bonded in a bent 120 degrees geometry to one Fe(6) and one P(4) atom. In the seventeenth O site, O(17) is bonded in a bent 120 degrees geometry to one Fe(3) and one P(5) atom. In the eighteenth O site, O(18) is bonded in a bent 120 degrees geometry to one Fe(5) and one P(5) atom. In the nineteenth O site, O(19) is bonded in a bent 150 degrees geometry to one Fe(6) and one P(5) atom. In the twentieth O site, O(20) is bonded in a bent 120 degrees geometry to one Fe(5) and one P(5) atom. In the twenty-first O site, O(21) is bonded in a bent 120 degrees geometry to one Fe(2) and one P(6) atom. In the twenty-second O site, O(22) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(6) atom. In the twenty-third O site, O(23) is bonded in a bent 120 degrees geometry to one Fe(4) and one P(6) atom. In the twenty-fourth O site, O(24) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(6) atom. In the twenty-fifth O site, O(25) is bonded in a distorted tetrahedral geometry to one Fe(1), one Fe(2), one Fe(4), and one Fe(6) atom. In the twenty-sixth O site, O(26) is bonded in a tetrahedral geometry to two equivalent Fe(3) and two equivalent Fe(5) atoms. Linkers: 24 [O]P([O])([O])=O. Metal clusters: 24 [Fe]. The MOF has largest included sphere 4.15 A, density 2.09 g/cm3, surface area 2088.45 m2/g, accessible volume 0.23 cm3/g