ON SECOND VIRIAL COEFFICIENT OF REAL GASES

The second virial coefficients of gases were evaluated by using the formerly developed principle of corresponding states.1 The intermolecular potential energy curve was expressed by means of a two-step square-well potential with one empirical parameter. The remaining constants of the potential, assumed to be universal constants, were derived from the properties of liquid and gaseous argon or methane. Satisfactory agreement with experimental data for all elements and compounds, also in presence of weak donor-acceptor interactions, proves the usefulness of the new principle. A table of values of the energy of vaporization (E*) and liquid molar volume (V*) at the reduced temperature T/Tc = 0.6 is given for 127 elements and compounds.