Thermophysical and magnetic studies of two paramagnetic liquid salts: [C4mim][FeCl4] and [P66614][FeCl4]

• Published in: Fluid phase equilibria 2013-07, Vol.350, p.43-50
• Main Authors: Cruz, M.M., Borges, R.P., Godinho, M., Marques, C.S., Langa, E., Ribeiro, A.P.C., Lourenço, M.J.V., Santos, F.J.V., Nieto de Castro, C.A., Macatrão, M., Tariq, M., Esperança, J.M.S.S., Canongia Lopes, J.N., Afonso, C.A.M., Rebelo, L.P.N.
• Format: Article
• Language: English
• Subjects: Decomposition temperature; Density; Heat capacity; Magnetic moment; Paramagnetism; Viscosity; Volumetric expansivity
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2013.03.001

•Thermophysical properties new data of two magnetic ionic liquids are presented.•New data on the magnetic properties using SQUID magnetometry are reported.•Density, viscosity and heat capacity are very different.•Both compounds are paramagnetic, due to the presence of Fe3+ ion.•Strong covalence effects in the [P66614]− cation were found. The density, heat capacity and viscosity of two magnetic ionic liquids sharing the same Fe (III)-containing anion, specifically, [C4mim][FeCl4] and [P66614][FeCl4], have been determined, along with their volumetric expansivity, and thermal decomposition temperatures. The magnetic properties of the two compounds have been studied using SQUID magnetometry. Both [C4mim][FeCl4] and [P66614][FeCl4] are paramagnetic, but while in the first case the magnetic moment value is 5.8μB/Fe, therefore close to that of Fe3+, for the latter it is only 4.8μB/Fe. The effective concentration of magnetic sites is almost three times greater for [C4mim][FeCl4] as compared to [P66614][FeCl4]. In this latter case, the experimental isothermal magnetization curves do not follow a Brillouin-type of behavior; alternatively, the results were discussed using the Spin Hamiltonian formalism in terms of both the distortion of the Iron site and covalence effects.