A 3-D organically templated mixed valence (Fe2+/Fe3+) iron phosphate with oxide-centered Fe4O(PO4)4 cubes: Hydrothermal synthesis, crystal structure, magnetic susceptibility, and Mossbauer spectroscopy of [H3NCH2CH2NH3](2)[Fe4O(PO4)(4)]center dot H2O

A 3-D, open framework, mixed valence iron-phosphate, [H3NCH2CH2NH3](2)[Fe4O(PO4)(4)]. H2O which contains organic ethylenediammonium dications in the framework voids, has been prepared via hydrothermal synthesis and has been characterized hp single-crystal X-ray diffraction, magnetic susceptibility, and variable temperature Mossbauer spectroscopy. Crystal data: tetragonal, space group I(4) over bar2$ m with a 10.1383(8) Angstrom, c = 9.628(1) Angstrom, V = 989.6(1) Angstrom(3), Z = 2,and R(R-w) = 7.7(6.5) for 276 reflections (I > 3 sigma(I)) and 32 variables. The fundamental building block of the structure is a novel cubane-like cluster with trigonal bipyramidal iron and tetrahedral phosphorus atoms lying at alternate vertexes of a cube with a tetrahedrally coordinated oxygen atom at the center of the cube. Each cluster is linked by eight Fe-O-P bonds that extend along what would be all [111] directions of the putative cube to eight similar clusters to form a framework that is only slightly distorted ted (by the presence of the organic cations) from cubic 43m symmetry. Mossbauer and ac magnetic susceptibility measurements show that equal amounts of valence trapped Fe2+ and Fe3+ are present, which undergo long range magnetic ordering at similar to 12 K.