In the present article, the adsorption, on different divided metal oxides, of several molecules : CO, CO₂, SO₂, N₂, CHCI₃, CH₃C≡N, pyridine, alcohols such as (CF₃)₂CHOH, H₂S, CH₃SH, NN₃ and pyrrole is reviewed. A careful analysis of the IR spectra shows that different types of species are formed due to the heterogeneity of the surface sites. In particular pyrrole and chloroform partly dissociate or decompose. In general, the molecules adsorb on surface cation-anion couples. Choice of probes such as CO₂ or (CF₃)₂CHOH allows one to select couples having a strong basic character. Results obtained with these two probes using different techniques like IR spectroscopy, microcalorimetry, gravimetry and volumetric measurements are compared. They both show that thoria, magnesia and zinc oxide are more basic than anatase and alumina. However, on basic oxides (MgO, ThO₂...), attention has to be paid to the possible formation of bulk carbonate when using CO₂. On amphoteric oxides (Al₂O₃, TiO₂...) CO₂ adsorption seems more specific than that of (CF₃)₂CHOH and S0₂. As for the heterogeneity of basic sites, use of probes like NH₃ or toluene allows one to detect specifically the most basic ones. It is also shown that ammonia and pyridine, generally used as probes for the measure of the acidity of catalysts, also adsorb on basic oxides through a dissociative chemisorption.