Electrosorption reactions of inorganic or organic systems can be analyzed in terms of the influence of the charge of the substance, charge transfer, and dipole terms. Macroscopic and thermodynamic data of the system can be correlated with molecular data. Important parameters are electronic data of the adsorbate, and the substrate and its structure, the solvent, and the electrode potential. After a short review on inorganic systems, the analysis of thermodynamic data of phenol and pyridine is given. Then, the pyridine adsorption on various crystal planes of Au and Ag is emphasized in this paper. The estimation of dipole terms and orientation is based on the literature and recent work. It can be shown that for pyridine adsorption on gold the charge transfer increases with increasing surface indices. The analysis of the charge transfer coefficient gamma, its potential dependence, and the Gibbs enthalpy of adsorption is in reasonable agreement. (C) 2003 Elsevier Science B.V. All rights reserved.