Ionic and molar volumes of room temperature ionic liquids

A large set of ionic volumes of the constituent ions of a variety of (non-protic) RTILs is used for the estimation of their molar volumes, hence their densities, at various temperatures by means of two fitting parameters only. The difference between the sum of the ionic volumes of the cation and the anion per mole and the actual molar volume is ascribed to the expansion of the RTIL on melting.