In DFT calculation of the charge transfer (Delta N), anions pose a special problem since their electron affinities are unknown. There is no method for calculating reasonable values of the absolute electronegativity (chi(A)) and chemical hardness (eta(A)) for ions from data of species themselves. We propose a new approach to the experimental measurement of chi(A) at the condition: Delta N = 0 at which eta values may be neglected and chi(A) = chi(Me). Electrochemical parameters corresponding to this condition may be obtained by the contact electric resistance method during in situ investigation of anion adsorption in the particular system anion-metal. (c) 2005 Elsevier B.V. All rights reserved.