High-temperature heat capacity of stannates ErSnO and TmSnO.

Erbium stannate ErSnO and thulium stannate TmSnO with a pyrochlore-type structure were produced by solid-phase synthesis by calcining stoichiometric mixtures of the respective oxides in air at 1473 K for 240 and 200 h. The high-temperature heat capacity of Er2Sn2O7 and TmSnO was studied by differential thermal calorimetry at 353-1000 K. From the experimental dependences C = f( T), the thermodynamic functions (enthalpy change, entropy change, and reduced Gibbs free energy) of oxide compounds were calculated. [ABSTRACT FROM AUTHOR]