The adsorption of N-2, O-2, and CO2 over graphite, amorphous carbons, aluminum oxide, and titanium dioxide is studied. The second gas-solid virial coefficients derived from the experimental adsorption isotherms are employed to determine the corresponding interaction parameters. The experimentally deduced parameters agree fairly well with the ones obtained through the combining rules for the diatomics adsorbed on graphite and amorphous carbons. On the other hand, large deviations are found for the systems involving oxide surfaces. The experimental data have been obtained in a wide temperature range (77.5 up to 292.5 K). The Bernal model is adopted to represent the different surfaces except in the case of graphite. The specific surface areas derived from this analysis are compared with the BET ones.