Heat capacity and entropy of CuF2 and CrF2 from 10 to 300 °K. Anomalies associated with magnetic ordering and evaluation of magnetic contributions to the heat capacity

Abstract

The low temperature heat capacity of CuF2 and of CrF2 is reported from 10 to 300 °K. Peaks in heat capacity associated with the onset of long-range magnetic order are observed at 70.90±0.05 °K for CuF2 and 49.26±0.01 °K for CrF2. Magnetic contributions to the heat capacity and entropy are evaluated and tabulated. Smoothed values of the total heat capacity, entropy, enthalpy, and Gibbs energy are tabulated between 10 and 300 °K. Values at 298.15 °K are: CuF2, C °P=15.65 cal °K−1 mole−1, S °=18.506 cal °K−1 mole−1, H°T−H°0=2891.8 cal mole−1; CrF2, C °P=15.48 cal °K−1 mole−1, S°=20.762 cal °K−1 mole−1, H°T−H°0−2911.5 cal mole−1.