Abstract An ionic, i. e. essentially electrostatic, approximation to donor-acceptor bonding between neutral species, ion-molecule interactions and corresponding solvation effects is forwarded. Drago's E-C equation for donor-acceptor reactions and the elimination of solvation procedure (ESP), presented by Drago et al., can consistently by incorporated in the general scheme. The theory yields further correct values for bulk ion-solvation enthalpies of cations H+,Li+,Na+,K+,Rb+ in water with the aid of ionization energies and electron affinities only. The formulae deduced for these types of chemical bonding represent the equivalent of the electronegativity-based theory for the description of ordinary chemical bonding between atoms, introduced earlier.