ABSTRACT

Thermodynamic functions of monoclinic terbium orthophosphate were determined based on the results of measurements of low temperature heat capacity (adiabatic calorimetry) and high temperature heat capacity (DSC). An irreversible exothermal effect accompanying the phase transition from monoclinic to tetragonal modification in the range 1350 1450 K was detected. A study of magnetic susceptibility in the temperature range 2 300 K indicated a lack of phase transformations in this region. Stability regions of monoclinic and tetragonal structural modifications were evaluated based on the temperature dependences of Gibbs energy of formation for both phases.

Compounds

#	Formula	Name
1	O4PTb	terbium orthophosphate

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	Triple point temperature, K ; Crystal 2			Crystal 2 Crystal 1 Air at 1 atmosphere	DSC	1
POMD	1	Mass density, kg/m3 ; Metastable crystal	Temperature, K; Metastable crystal Pressure, kPa; Metastable crystal		Metastable crystal	X-ray diffraction	1
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Vacuum adiabatic calorimetry	137
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Vacuum adiabatic calorimetry	44
POMD	1	Molar entropy, J/K/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Vacuum adiabatic calorimetry	44
POMD	1	Molar enthalpy, kJ/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Vacuum adiabatic calorimetry	44
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Small sample (50 mg) DSC	116
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Small sample (50 mg) DSC	35
POMD	1	Molar entropy, J/K/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Small sample (50 mg) DSC	35
POMD	1	Molar enthalpy, kJ/mol ; Metastable crystal	Temperature, K; Metastable crystal	Pressure, kPa; Metastable crystal	Metastable crystal	Small sample (50 mg) DSC	35

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Thermodynamic properties and phase transition of monoclinic terbium orthophosphate

Gavrichev, K. S., Ryumin, M. A., Khoroshilov, A. V., Tyurin, A. V., Efimov, N. N., Gurevich, V. M., Nikiforova, G. E., Guskov, V. N., Golushina, L. N., Bryukhanova, K. I., Kritskaya, A. P.

ABSTRACT