Figure shows the results of the dipolar contribution for 135 electrolytes. (The fit parameters are shown in Tables and in the Appendix. The investigated electrolytes are given in Table .) In panel A we show the dipolar contribution to ln γ ± for four electrolytes with increasing interaction strength from CsI to LiCl. The cross-over point x Dipole h (dashed vertical line) marks a boundary: dipoledipole interaction becomes unfavorable for higher concentrations and complex (i.e. quadrupole and octupole) interactions become more important. The droplet size of the observation volume where this happens is determined by 1/x Dipole h . With increasing ion-ion and ion-water interactions, the cross-over shifts toward lower concentrations. This is in qualitative agreement with findings from a combined SAXS and simulation study (Fig. in ) showing that a cross-over from Debye-Hückel to more complex behavior occurs at lower concentrations for more strongly interacting ions.