Thermodynamics of the lanthanide trifluorides. II. The heat capacity of praseodymium trifluoride PrF3from 5 to 350thinsp;deg;K

摘要

The heat capacity of PrF3was measured by aneroid adiabatic calorimetry from 5 to 350thinsp;deg;K. The following results were obtained for PrF3(c) at 298.15thinsp;deg;K: the heat capacityCpdeg;= (92.65 plusmn;0.09) Jthinsp;deg;Kminus;1thinsp;moleminus;1, the entropy Sdeg;= (121.22plusmn;0.12) Jthinsp;deg;Kminus;1thinsp;moleminus;1, the enthalpy (HTdeg;minus;H0deg;)= (17thinsp;946plusmn;18) Jthinsp;moleminus;1and the Planck function minus;(GTdeg; minus;H0deg;)/T=(61.02plusmn;0.06) Jthinsp;deg;Kminus;1thinsp;moleminus;1. Recommended thermal functions from 400 to the melting temperature, 1672thinsp;deg;K, are presented in tabular form. The excess heat capacity due to the internal electronic energy levels of Pr3+in PrF3is calculated from spectroscopic data and compared with excess heat capacity derived from calorimetric results.