Magnetic ionic liquid

The ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate was identified by Satoshi Hayashi and Hiro-o Hamaguchi of the University of Tokyo in 2004 as magnetic ionic liquid. It can be obtained from 1-butyl-3-methylimidazolium chloride and ferric chloride. It has quite low water solubility an thus can be considered as hydrophobic ionic liquid.

Due to the presence of high spin FeCl₄⁻, the liquid is paramagnetic and a magnetic susceptibility of 40.6 × 10⁻⁶ emu g⁻¹ is reported. A simple magnet suffices to attract the liquid in a test tube.