ABSTRACT

The heat capacities of the lanthanide zirconates Gd2Zr2O7 and Eu2Zr2O7 with pyrochlore structure were measured by adiabatic calorimetry and the hybrid adiabatic relaxation method in the temperature range (0.3 to 400) K. A thermal anomaly was observed for Gd2Zr2O7 below T = 15 K. From the measurements the thermodynamic functions of Gd2Zr2O7 and Eu2Zr2O7 were determined. By combining our results with the heat capacity data of La2Zr2O7, the lattice component of the heat capacity and the entropy were derived for the lanthanide series Ln2Zr2O7 (Ln=La to Gd). The Schottky contributions were derived for Ce2Zr2O7, Nd2Zr2O7 and Eu2Zr2O7 by subtracting the lattice component from the experimental data, and compared to the values calculated from the crystal field energy levels.

Compounds

#	Formula	Name
1	Gd2O7Zr2	gadolinium zirconate
2	Eu2O7Zr2	europium zirconate

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	VADIAC:UFactor:4	293
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	VADIAC:UFactor:4	47
POMD	1	Molar enthalpy, kJ/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	VADIAC:UFactor:4	47
POMD	1	Molar entropy, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	VADIAC:UFactor:4	47
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	VADIAC:UFactor:4	229
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	VADIAC:UFactor:4	47
POMD	2	Molar enthalpy, kJ/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	VADIAC:UFactor:4	47
POMD	2	Molar entropy, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	VADIAC:UFactor:4	47

Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

The low-temperature heat capacity of some lanthanide zirconates

Lutique, S., Javorsky, P., Konings, R. J. M., Krupa, J.-C., van Genderen, A.C.G., Miltenburg, J. C.[J. C. van], Wastin, F.

ABSTRACT