have been studied, using cyclic voltammetry (CV), electrochemical scanning tunneling microscopy (EC-STM), and reflectance anisotropy spectroscopy (RAS). At cathodic potentials more positive than the hydrogen evolution reaction a bare copper surface (1× 1) structure is found by EC-STM. At anodic potentials more negative than the copper(II) dissolution reaction a furrowed structure is found. The governing factor to rule Cu(110)-Cl interface processes, is discussed as an interplay between Cl¯ adsorption / desorption, the dynamic rearrangement of the surface atoms on the substrate and strain in order to reduce the surface energy. The information provided by EC-STM and RAS complements that of CV, supplies detailed information on the surface morphology and correlates peaking Faraday currents to structural modifications. Furthermore RAS and EC-STM show changes in the surface appearance in a potential range where no specific charge transfer is observed. CV indicates that the Cu(110) surface chemistry compares much better to amorphous Cu than that of the more stable (100) and (111) surfaces, respectively.