THE HEAT-CAPACITY AND DERIVED THERMODYNAMIC FUNCTIONS OF LA2ZR2O7 ANDCE2ZR2O7 FROM 4 TO 1000 K

The heat capacities of cerium and lanthanum zirconate (Ce2Zr2O7 and La 2Zr2O7) were measured from 4 to 400 K by adiabatic calorimetry. The de rived thermodynamic functions, H degrees, S degrees and {G degrees - H degrees(0)}/T were calculated. The standard molar entropies at 298.15 K were determined as 230.21 +/- 0.46 J/mol . K and 238.53 +/- 0.48 J/m ol . K. Enthalpy increments relative to 298.15 K were measured by drop calorimetry from 500 to 900 K. From these data the thermodynamic func tions; including the enthalpy and Gibbs free energy of formation of th e two compounds were derived for temperatures up to 1000 K. Copyright (C) 1997 Elsevier Science Ltd.