Gas-phase ion pairs

Ab initio MD (AIMD) simulations on IC nimllCII were carried out by Del Popolo et al. [138], The local structure around the cation showed significant differences compared to both the classical calculations and the neutron results. In particular, and unlike the gas-phase ion pair, chloride ions tended to be located near a ring C-H proton in a position suggesting hydrogen bonding. For their DFT... 

Enthalpy of vaporization this is counterintuitive for ionic liquids, but they can be distilled and have a small but measurable vapor pressure. It seems that ionic liquids vaporize by forming neutral ionic pairs which leave the bulk fluid. Protic ionic liquids may also form two different molecules by acid-base reactions e.g. RNH + NO —t RNH3 + HNO3. Vaporization enthalpies can be calculated by extracting the enthalpy of the liquid and by subtracting a perfect gas calculation of the enthalpy of an equal number of gas phase ion pairs. 

Although these new calculations will not be the last ones, we can certainly conclude that the favoured candidates for gas phase ion pairs essentially result from combinations of tertiary amines with HCl, HBr or... 

List the following gas-phase ion pairs in order of the quantity of energy released when they form from separated gas-phase ions. Start with the pair that releases the least energy. Na F , Mg +F, Na+O, Mg +O, Al +O . 

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