Synthesis and Structure of the First Three-legged Low-dimensional Iron Phosphate, [H3N(CH2)3NH2(CH 2)2NH2(CH2)3NH 3][Fe3F6(HPO4)2(PO 4)]·3H2O

A hydrothermal reaction of iron acetylacetonate, phosphoric acid, HF, N,N�-bis(3-aminopropyl)ethylenediamine and water at 150°C gave rise to a new iron phosphate, [H3N(CH2)3NH 2(CH2)2NH2(CH2) 3NH3][Fe3F6(HPO4) 2(PO4)] · 3H2O (I). The structure consists of Fe(1)O4F2, Fe(2)O3F3 octahedral and P(1)O3(OH) and P(2)O4 tetrahedral building units connected through their vertices to form fragments of tancoite-type units. The tancoite-type units are linked through the phosphate tetrahedra forming an unusual iron phosphate with a hitherto unknown low-dimensional structure with three-iron center.Magnetic studies indicate a complex behavior at low temperature and the high-temperature data (150 - 300 K) has a Curie-Weiss behavior. The calculated room temperature magnetic moment is 6 μB per Fe atom, and the Neel temperature, TN = 46K. Crystal data: orthorhombic, space group = I212121 (no. 24), a = 9.9042(11), b = 12.8865(14), c = 19.783(2) �, U = 2524.9(5), Z = 4.