This paper reviews thermodynamic, spectroscopic and X-ray diffraction
studies of SO42-, Cl-, Br- and I- adsorption at the Au(111) electrode
surface. The thermodynamic experiments provided information about surf
ace concentrations of specifically adsorbed anions, Gibbs energies of
adsorption and the numbers of unit charge flowing to the interface per
one adsorbed anion. Second harmonic generation and surface X-ray scat
tering revealed the affect of ionic adsorption on the electronic and c
rystallographic structure of the interface. The atomistic information
derived from these microscopic studies was used to discuss the thermod
ynamic data and to verify the theoretical models of the interface. It
has been shown that complete description of ionic adsorption at metal
electrodes requires a concerted use of the macroscopic and microscopic
techniques. (C) 1998 Published by Elsevier Science Ltd. All rights re
served.