The metal support interaction was analyzed by means of AIM and ELF approaches taking Pd adsorbed on MgO(0 0 1), alpha-Al2O3 (0 0 0 1) and SiO2 surfaces as examples of simple ionic, complex ionic and covalent oxide surfaces. respectively. On the most favorable adsorption sites, the polysynaptic basins found indicate the presence of chemical bonds. The basins populations are low in the case of the two ionic oxides while on a specific site of the SiO2 surface, a polysynaptic basin with similar to2 electrons was found illustrating the variety and richness of the chemical bonding between a metal and an oxide. (C) 2004 Elsevier B.V. All rights reserved.