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 ${\mathrm{H°}}_T{\mathrm{\hspace{0.17em}-\hspace{0.17em}H°}}_{298}{\mathrm{,\; Cp,\; S°}}_T{\mathrm{\hspace{0.17em}-\hspace{0.17em}S°}}_{298}$ , and ${\mathrm{-\hspace{0.17em}(F°}}_T{\mathrm{\hspace{0.17em}-\hspace{0.17em}H°}}_{298}\mathrm{)\hspace{0.17em}/\hspace{0.17em}T}$ 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.