Dynamic differential calorimetry of intermetallic compounds: III. Heats of formation,heats and entropies of fusion of REIn3 and RETl3 compounds

Dynamic differential calorimetry has been employed to evaluate the heats of formation, heats and entropies of fusion of REIn₃ and RETl₃ compounds. The results obtained have been estimated to be corrected to within ±5–6%. The general trend, for both these series, is a decrease in the heat of formation from La to Lu which is correlated with the magnitude of the lanthanide contraction in these compounds. A simple correlation has been found between the heats of formation of REX₃ compounds and the ionic radii of the elements involved.