Synthesis, Crystal Structure and Magnetic Properties of a new Hydroxylammonium Fluoroferrate

摘要

This paper reports on the synthesis of a new hydroxylammonium fluoroferrate, with the formula (NH3OH)3FeF6, obtained after dissolving iron powder in hydrofluoric acid and adding solid NH3OHF. This new compound has been characterized by chemical and thermal analysis, single-crystal X-ray diffraction, and magnetic measurements. The title compound crystallizes trigonal, R3c, with cell parameters a = 11.4154(2) A, c = 11.5720(2) A, Z = 6. The structure consists of NH3OH~+ cations and isolated FeF_6~(3-) octahedra in which the central ion lies on a threefold axis. The oxygen and nitrogen atoms of the hydroxylammonium cations are donors of hydrogen bonds to fluoride anions, resulting in a network of hydrogen bonds between counterions. The effective magnetic moment μ_(eff) = 5.8 BM was calculated and perfectly matches the expected value of high-spin Fe(III) ions. The thermal decomposition of the compound was studied by TG, DSC, and X-ray powder diffraction.