A comparison of methods for the estimation of the enthalpy of formation of rare earth compounds

Rare earth elements are helping drive the global transition towards a greener economy. However, the way in which they are produced is far from being considered green. One of the major obstacles to developing greener production methods and the design of novel processes and materials involving rare earth elments is the limited thermodynamic data available. In the present work, we apply a suite of methods to estimate the enthalpy of formation of several rare earth compounds, including a new method based on a linear relationship, established by the authors. Experimental values of the enthalpy of formation of LnCl3, LnOCl, LnPO4, Ln2O2S, Ln2O2CO3 and NaLnO2 were collated and used to assess the accuracy of the different methods, which were then used to predict values for compounds for which no data exists. It is shown that Mostafa´s et al1 group contribution method and the linear relationship proposed by the authors give the lowest mean absolute error (