A method is proposed for the valuation of net atomic charge in chemical compounds, based on XPS measurements of two energy levels for the same atomic species and on the evaluation of their difference. This approach, by considering two core levels, allows us to cancel the Madelung term and any other external potential from the electrostatic equation that rules the chemical shift of the binding energy. In this way, it directly relates the experimental shift with the net charge on the considered atomic species. The approximation that Madelung potential does not vary significantly from one core level to another one is used. The method has been applied to solid compounds containing silicon and to aluminosilicates having different counter‐ions and different Si/Al ratios. The experimental data of net charges have been compared, where possible, with Pauling and Sanderson charges obtained from electronegativity data. Copyright © 2000 John Wiley & Sons, Ltd.