The adsorption behaviour of Cl-, Br-, I- and SCN- anions on the Bi(0 0 1) single crystal plane from aqueous solution has been studied by impedance spectroscopy. The values of the surface excess, the Gibbs energy of adsorption of anions, the electrosorption valency and the effective dipole moment of the dipole formed by an adsorbed anion and its image charge in the Bi(0 0 1) plane have been calculated using mainly the electrode potential E as an independent electrical variable. It was found that the inner layer characteristics depend noticeably on the chemical composition, geometrical shape and electrical charge distribution of an anion adsorbed at the Bi(0 0 1) plane. A comparison with the data for the Bi(1 1 1) \ surface-active electrolyte interface has been given. (C) 2003 Elsevier Science B.V. All rights reserved.