High-Temperature Heat Contents and Related Thermodynamic Functions of Seven Trifluorides of the Rare Earths: Y, La, Pr, Nd, Gd, Ho, and Lu

The high-temperature heat contents of high-purity YF3, LaF3, PrF3, NdF3, GdF3, HoF3, and LuF3 were measured from 100–1600°C. The heat capacity, heats of transition, heats of fusion, and related thermodynamic functions were calculated. The smoothed values of H°T − H°298, Cp, S°T − S°298, and − (F°T − H°298) / T are tabulated at 100° intervals. A comparison of the values for the transition temperature, melting points, and lattice parameters of the higher-purity fluorides of this work with those of less pure fluorides indicated that a reduction in oxygen content does not affect these properties.