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 H°T−H°298.15, Cp, S°T−S°298.15, and −(F°T−H°298.15)/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.

Experimental study of the enthalpy of lutetium trifluoride in solid and liquid states

“…The high temperature caloric properties of rare-earth fluorides (REFs) in the solid and liquid states were studied previously [1,2]. It was seen from the analysis of results that the heat capacity changes in solid-solid transitions and that the heat capacity of the melts vary irregularly with atomic number of the RE cations.…”

Optical and Computational Studies of Elastic and Defect Properties of Materials

“…The specific heat anomalies for CeF3 [20] and NdF3 [21] are similar, but have a smaller magnitude and a different functional form to that of LaF3 obvious and computational simulations would be valuable in developing an explanation of these effects.…”

“…Theoretical and computational approaches using surface Green's functions [26-281 provide a comprehensive understanding of these sometimes [20] and NdFl [21].…”

Investigation of the Evaporation Thermodynamics of Erbium Trifluoride and Thulium Trifluoride by Knudsen Effusion Mass Spectrometry and Matrix Isolation Infrared Spectroscopy

“…Table 6 shows a comparison of transition temperatures, melting points, as well as the enthalpy changes of transition and melting determined by us using KEMS, and by other investigators using DTA and calorimetry.". 21 In order to obtain the transition and melting points with reasonable accuracy, the samples had to be fluorinated in a fluorine atmosphere to decompose oxyfluoride contamination. The oxyfluorides are slowly formed by reaction between the fluorides and air.…”