Hydrothermal synthesis, structure, and magnetic properties of a novel monodimensional iron phosphate: [FeF(HPO4)(2),N2C3H12,(H2O)(x)] (X approximate to 0.20) (ULM-14)

ULM-14 or [FeF(HPO4)(2),N2C3H12,(H2O)(x)] (X approximate to 0.20) was synthesized by the hydrothermal method (24 h, 453 K) under autogenous pressure. ULM-14 crystallizes in the orthorhombic system (space group Pmca, No. 57) with cell parameters a = 7.221(1) Angstrom, b = 8.655(1) Angstrom, c = 19.329(2) Angstrom, and Z = 4. Its structure, solved by single-crystal X-ray diffraction, results from isolated single [FeF(HPO4)(2)](2-), chains of the tancoite type, with diprotonated amines inserted in between. Mossbauer spectrometry clearly evidences the presence of high-spin-state Fe3+ ions in octahedral coordination and the remaining water molecules. Both magnetic susceptibility and Mossbauer results indicate that ULM-14 behaves as a paramagnet above 2 K, the intrachains interactions being antiferromagnetic.