The performance of cubic equations of state on the critical isotherms of pure fluids

The potential of cubic equations of state for describing the critical isotherm of a pure fluid has been examined. Some mathematical results are derived which show that in this respect such equations have fundamental and far-reaching limitations, separate from their obvious failure in the critical region. The implications become clear in a numerical test of various equations on experimental critical-isotherm data. The present study provides insight into the relationship between the performance of a cubic equation of state and its parametric structure.