The first organically templated layered iron phosphate: Hydrothermal synthesis, structure, magnetic properties, and the Mössbauer spectrum of [H3NCH2CH2NH3] 0.5[Fe(OH)(PO4)]

The first organically templated, layered iron phosphate [H₃NCH₂CH₂NH₃] _0.5[Fe(OH)(PO₄)], 1, has been prepared and characterized via single crystal X-ray diffraction, variable temperature magnetic susceptibility measurements, and Mössbauer spectroscopy. Phosphate 1 is synthesized from the hydrothermal reaction of FeCl₃, H₃PO₄, ethylenediamine, and H₂O in the mole ratio 1:3.6:4.2:444 for 64 h at 160°C and exhibits a layered structure consisting of infinite chains of edge-sharing {FeO₆} octahedra linked into finite 2-D sheets by {PO₄} tetrahedra that possess terminal P=O groups which protrude into the interlamellar space. The infinite edge-sharing chains display a pairwise puckering resulting from the presence of trans μ²-OH groups arranged in a zig-zag fashion along the chain. The charge compensating ethylenediammonium cations contact both adjacent layers via an elaborate and complicated hydrogen bonded network. Crystal data for 1: FePO₅NCH₆, monoclinic, space group P2₁/c, a = 4.5010(7) Å, b = 6.114(1) Å, c = 18.460(3) Å, β = 94.59(1)°, V = 56.4(1) Å, Z = 2, d_calc = 2.608 g · cm^-3; 1650 reflections, R = 0.049. Variable temperature Mossbauer data, dc magnetization, and ac susceptibility measurements show that 1 undergoes a transition to a weak ferromagnetic State near 30 K.