ABSTRACT

The investigation of the heat capacity of a natural specimen of copper phosphate - pseudo-malachite Cu5(PO4)2(OH)4 in the temperature range between 4.2 K and 320 K has been carried out by the method of low-temperature adiabatic calorimetry. Tabulated values of the heat capacity and thermodynamic functions of the mineral including the changes of entropy and enthalpy and the Gibbs function of free energy have been calculated. The standard values of thermodynamic functions of pseudomalachite at O=298.15 K are Ndeg o,m = (385.43+-0.41) J mole1 K1 , .T0 Sdeg m = (412.16+-0.61) J mole1 K1 , .T 0Ideg m = (63681.5+-57.0) J mole1 , Fdeg m = (198.57+-0.47) J mole1 K1 . In the low-temperature area 0 less than (T /K) less than 22.69 an anomaly has been registered in the variation of the heat capacity of the mineral, for which the lattice constituent has been determined. The contribution of anomalous component into entropy and enthalpy of the mineral is .Str = (5.772+-0.081) J mole1 K1 , .Itr = (29.94+-0.42) J mole1 .

Compounds

#	Formula	Name
1	Cu5H4O12P2	copper hydroxide phosphate (Cu5(OH)4(PO4)2)

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	Vacuum adiabatic calorimetry	549
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Vacuum adiabatic calorimetry	57
POMD	1	Molar entropy, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Vacuum adiabatic calorimetry	57
POMD	1	Molar enthalpy function {Hm(T)-Hm(0)}/T, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Vacuum adiabatic calorimetry	57

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Low temperature measurements of the heat capacity and thermodynamic functions of pseudomalachite Cu5(PO4)2(OH)4

Bissengaliyeva, M. R.[Mira R.], Gogol, D. B., Bekturganov, N. S.

ABSTRACT