  A comparison of two thermodynamic models is presented using the water-cesium
nitrate system as case study. Both models were able to model the thermodynamic
properties such as the osmotic coefficient, vapor pressure, mean activity
coefficient and solubility with good accuracy. We show that it is possible to
reproduce the temperature dependency of the properties using a simple set of
parameters in the case of Extended UNIQUAC. Furthermore, COSMO-RS-ES is a
completely predictive model adjusted to data at 298.15 K, which is applied for
the first time to other temperatures.
