Neeraj Rai's paper entitled "Critical behaviour and vapour-liquid coexistence of 1-alkyl-3-methylimidazolium
bis-(triﬂuoromethylsulfonyl)amide ionic liquids via Monte Carlo simulations" just appeared (Faraday Discussions, 2012, 154, 53-69). In this paper, Neeraj computes the vapor-liquid phase behavior of a series of ionic liquids. He shows that the critical point and enthalpy of vaporization actually decrease with increasing size of the cation, which is opposite that observed with alkanes. This is due to a competition between Coulombic and van der Waals forces. He also shows that at the highest pressures (and temperatures) significant clustering occurs in the vapor phase, but that single ion pairs are the dominant vapor species at lower temperatures and pressures.