ABSTRACT

Specific heat capacities (Cp) of polycrystalline samples of BaCeO3 and BaZrO3 have been measured from about 1.6K up to room temperature by means of adiabatic calorimetry. We provide corrected experimental data for the heat capacity of BaCeO3 in the range T < 10K and, for the first time, contribute experimental data below 53K for BaZrO3. Applying Debye s T3-law for T.0K, thermodynamic functions as molar entropy and enthalpy are derived by integration. We obtain Cp = 114.8 (+-1.0) J mol-1 K-1, S. = 145.8 (+-0.7) J mol-1 K-1 for BaCeO3 and Cp = 107.0 (+-1.0) J mol-1 K-1, S. = 125.5 (+-0.6) J mol-1 K-1 for BaZrO3 at 298.15 K. These results are in overall agreement with previously reported studies but slightly deviating, in both cases. Evaluations of Cp(T) yield Debye temperatures and identify deviations from the simple Debye-theory due to extra vibrational modes as well as anharmonicity. The anharmonicity turns out to be more pronounced at elevated temperatures for BaCeO3. The characteristic Debye temperatures determined at T=0K are T0 = 365 (+-6)K for BaCeO3 and T0 = 402 (+-9)K for BaZrO3.

Compounds

#	Formula	Name
1	BaO3Zr	barium zirconium(IV) oxide
2	BaCeO3	barium cerium(IV) oxide

Datasets

The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type	Compound-#	Property	Variable	Constraint	Phase	Method	#Points
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	375
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	21
POMD	1	Molar enthalpy, kJ/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	21
POMD	1	Molar entropy, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	21
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	365
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	21
POMD	2	Molar enthalpy, kJ/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	21
POMD	2	Molar entropy, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Small (less than 1 g) adiabatic calorimetry	21

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Thermodynamic properties of BaCeO3 and BaZrO3 at low temperatures

Ahrens, M., Maier, J.

ABSTRACT