Cationic and anionic effects on the homogeneous nucleation of ice in aqueous alkali halide solutions

Homogeneous ice nucleation temperatures (THs) of aqueous alkali halide solutions were measured as a function of salt concentration. Cationic effect on TH increases with decreasing ionic radius: Cs+<Rb+<K+<Na+<Li+ while anionic effect becomes larger with increasing ionic radius: Cl−<Br−<I−. There is almost a linear relation between TH and 1/r+ (or 1/r−) for the same halide (or alkali) solutions up to high salt concentrations (r+ and r− are ionic radii of alkali and halide ions, respectively).