Hydrothermal Synthesis, Structure, and Magnetic Properties of a Novel Monodimensional Iron Phosphate: [FeF(HPO₄)₂,N₂C₃H₁₂,(H₂O)<i>_x</i>] (<i>x</i> ≈ 0.20) (ULM-14)

Abstract

ULM-14 or [FeF(HPO(4))(2),N(2)C(3)H(12),(H(2)O)(x)()] (x approximately 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) Å, b = 8.655(1) Å, c = 19.329(2) Å, and Z = 4. Its structure, solved by single-crystal X-ray diffraction, results from isolated single [FeF(HPO(4))(2)](2)(-)(n)() chains of the tancoite type, with diprotonated amines inserted in between. Mössbauer spectrometry clearly evidences the presence of high-spin-state Fe(3+) ions in octahedral coordination and the remaining water molecules. Both magnetic susceptibility and Mössbauer results indicate that ULM-14 behaves as a paramagnet above 2 K, the intrachains interactions being antiferromagnetic.