Thermodynamic assessment of LiCl-NdCl3 and LiCl-PrCl3 quasi-binary systems

The LiCl-NdCl3 and LiCl-PrCl3 binary systems as well as the end-member components NdCl3 and PrCl3 have been thermodynamically optimized by a computer-operated least squares method. The present evaluated thermodynamic functions for NdCl3 and PrCl3 can explain all reliable experimental thermodynamic data quite well and can be used outside the temperature range where the phases are thermodynamically stable. Based on the structure information, liquid phases in both LiCl-NdCl3 and LiCl-PrCl3 binary systems are described by the two sub-lattice ionic solution model (Li+)P: (Cl−, LnCl6−3, LnCl3)Q, (Ln = Nd, Pr). The end-member-based solid solutions are treated as pure compounds since the mutual solubility between them is virtually limited. A set of parameters consistent with most experimental data on both phase diagrams and thermodynamic properties have been obtained for the considered systems. Comparison between the calculated results and experimental data is also presented.