AbstractPrevious investigation of transfer of electron density accompanying hydrogen bond formation has been extended to complexes between positively charged donors and neutral acceptors, as well as to the complexes between a neutral donor and a negatively charged acceptor molecules. The amount of transferred electron density from acceptor to donor for the charged complexes may be adequately described by the same exponential dependence on the equilibrium distance between the hydrogen atom and the nearest atom of the acceptor molecule as it was found for neutral complexes. Relation of the H‐bond energy to electron density at the H‐bond critical point was dependent on the sign of Laplacian of the electron density. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010