Studies on the thermodynamic properties of the ionic liquid BMIGaCl4

An ionic liquid (IL) BMIGaCl4 was prepared by directly mixing GaCl3 and 1-methyl-3-butylimidazolium chloride with molar ratio of 1/1 under argon atmosphere. The densities and surface tensions of this pure ionic liquid were determined in the temperature range of 268.15 to (338.15 +/- 0.1) K. A new theoretical model of ionic liquids, an interstice model, was applied to calculate the thermal expansion coefficient of IL BMIGaCl4, a, and the magnitude order of its value calculated by the theory was the same as experimental one. Both Raman scattering and ab initio calculations indicate that GaCl4- is the only species containing Ga in the ionic liquid BMIGaCl4.