Thermal properties of cerium and thorium tellurates

Enthalpy increment measurements on CeTe₂O₆ (s) and ThTe₂O₆ (s) were carried out using a Calvet micro-calorimeter. The enthalpy increment values were least squares analyzed, with the constraint that H⁰(T)−H⁰ (298.15 K) at 298.15 equals 0 and C_p⁰ (298.15 K) is equal to the value estimated by Kellog’s method.The dependence of the enthalpy increment with temperature can be given as:

H⁰(T)−H⁰ (298.15 K)(J mol⁻¹)=189.95 T (K)+15.226×10⁻³ T² (K) +15.414×10⁵/T (K)−63157 (CeTe₂O₆ (s), 391.5–848.0 K)

H⁰(T)−H⁰ (298.15 K)(J mol⁻¹)=191.34 T (K)+14.993×10⁻³ T² (K) +14.668×10⁵/T (K)−63300 (ThTe₂O₆ (s), 391.5–909.3 K)

Molar heat capacity C_p⁰(T), S(T) and Gibb’s free energy functions were evaluated.