Equation of state and thermodynamic properties of pure D2O and D2O+H2O mixtures in and beyond the critical region

A parametric crossover model is adapted to represent the thermodynamic prop erties of pure D2O in the extended critical region. The crossover equation of state for D2O incorporates scaling laws asymptotically close to the crit ical point and is transformed into a regular classical expansion far From t he critical point. An isomorphic generalization of the law of corresponding states is applied to the prediction of thermodynamic properties and the ph ase behavior of D2O + H2O mixtures over a wide region around the locus of v apor-liquid critical points. A comparison is made with experimental data fo r pure D2O and for the D2O + H2O mixture. The equation of slate yields a go od representation of thermodynamic property data in the range of temperatur es 0.8T(c)(x) less than or equal to T less than or equal to 1.5T(c)(x) and densities 0.35 rho(c)(x) less than or equal to rho less than or equal to 1. 65 rho(c)(x).