The potential energy functions of CO–CO, CO 2–CO 2, and N 2O–N 2O systems have been determined via the inversion of reduced viscosity collision integrals at zero pressure and fitted to obtain analytical potential forms. The potentials produce viscosity, thermal conductivity, self-diffusion coefficient, and second virial coefficients of carbon monoxide, carbon dioxide, and nitrous oxide over wide temperature ranges within experimental errors. The potentials of carbon monoxide and carbon dioxide have been compared with the recently obtained ab initio potentials and the potential of nitrous oxide has been compared with the Stockmayer potential. We have also derived very accurate equations for viscosity, self-diffusion coefficient, and second virial coefficient of CO, CO 2, and N 2O in a wide temperature range.