Mössbauer Spectroscopy and X-ray Diffraction Study of 57Fe-Labeled Tetrachloroferrate(III)-Based Magnetic Ionic Liquids

Four 57Fe-labeled tetrachloroferrates(III) of organic cations (1-butyl-3-methyl-imidazolium, 1-allyl-3-methylimidazolium, 1-methyl-1-propylpyrrolidinium, tetraphenyl­phosphonium) were examined by temperature-dependent Mössbauer spectroscopy. The hyperfine and dynamic parameters of the iron(III) site were determined. Single crystal X-ray diffraction data of [Ph4P][FeCl4] were collected at four temperatures (295, 223, 173, and 123 K), and the dynamics of the iron atom inferred from the Mössbauer data and the single crystal Ui,j parameters have been compared.