High temperature enthalpies and related thermodynamic functions of the trifluorides of Sc, Ce, Sm, Eu, Gd, Tb, Dy, Er, Tm, and Yb

Abstract

The high temperature enthalpies of high purity ScF₃, CeF₃, SmF₃, GdF₃ (redetermined), TbF₃, DyF₃, ErF₃, TmF₃, and YbF₃ were measured from 100 to 1600°C and EuF₃ from 100 to 975°C. The thermal data for the other fluorides in the rare earth series were reported earlier from this laboratory. The heat capacity, enthalpies of transition and fusion, and related thermodynamic functions were calculated. The smoothed values of ${\mathrm{H°}}_T{\mathrm{-H°}}_{\text{298.15}}$ , $C_p{\mathrm{,\; S°}}_T{\mathrm{-S°}}_{\text{298.15}}$ , and ${\mathrm{-(F°}}_T{\mathrm{-H°}}_{\text{298.15}}\mathrm{)/T}$ are tabulated at 100° intervals. The melting points, transition temperatures, and lattice parameters of the high purity fluorides prepared in this study were determined.