A parametric crossover model is adapted to represent the thermodynamic properties of pure D20 in the extended critical region. The crossover equation of state for D20 incorporates scaling laws asymptotically close to the critical point and is transformed into a regular classical expansion far from the critical point. An isomorphic generalization of the law of corresponding states is applied to the prediction of thermodynamic properties and the phase behavior of D20 + H20 mixtures over a wide region around the locus of vapor-liquid critical points. A comparison is made with experimental data for pure D20 and for the D20 + H20 mixture. The equation of state yields a good representation of thermodynamic property data in the range of temperatures 0.8Tc(x) <= T <= 1.5Tc(x) and densities 0.35 rho-c(x) <= rho <= 1.65 rho-c(x).

• Contact: Allan Harvey