ABSTRACT

Differential scanning calorimetry (DSC) and drop calorimetry were performed on Na2MoO4 and CaMoO4 (powellite). The heat capacity of alpha-Na2MoO4 by DSC measurement almost agreed with that by previous drop calorimetry. The heat capacity and enthalpy of Na2MoO4 were optimized as a function of temperature from 273 K to 1550 K by combining new calorimetric data and published data. The heat of fusion of CaMoO4 was 95.8 +- 1.6 kJ*mol-1 at melting point (1744 +- 5 K) and the heat capacity of the melt was 180.6 +- 5.1 J*mol -1 K-1. The heat capacity and enthalpy of CaMoO4 were formulated as a function of temperature in the range of 273 K to 1875 K.

Compounds

#	Formula	Name
1	MoNa2O4	sodium molybdate
2	CaMoO4	calcium molybdate(VI)
3	O2Si	silicon dioxide

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 enthalpy of transition or fusion, kJ/mol ; Crystal 2			Crystal 2 Crystal 1 Air at 1 atmosphere	Drop ice or diphenyl ether calorimetry	1
POMD	1	Molar enthalpy of transition or fusion, kJ/mol ; Crystal 1			Crystal 1 Liquid Air at 1 atmosphere	Drop ice or diphenyl ether calorimetry	1
POMD	1	Triple point temperature, K ; Crystal 2			Crystal 2 Crystal 1 Air at 1 atmosphere	Drop calorimetry	1
POMD	1	Triple point temperature, K ; Crystal 1			Crystal 1 Liquid Air at 1 atmosphere	Drop calorimetry	1
POMD	1	Triple point temperature, K ; Crystal 3			Crystal 3 Crystal 2 Air at 1 atmosphere	DSC	1
POMD	1	Triple point temperature, K ; Crystal 4			Crystal 4 Crystal 3 Air at 1 atmosphere	DSC	1
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal 4	Temperature, K; Crystal 4	Pressure, kPa; Crystal 4	Crystal 4	DSC	176
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal 3	Temperature, K; Crystal 3	Pressure, kPa; Crystal 3	Crystal 3	DSC	42
POMD	1	Molar heat capacity at constant pressure, J/K/mol ; Crystal 2	Temperature, K; Crystal 2	Pressure, kPa; Crystal 2	Crystal 2	DSC	17
POMD	1	Molar enthalpy, kJ/mol ; Crystal 2	Temperature, K; Crystal 2	Pressure, kPa; Crystal 2	Crystal 2	Drop ice or diphenyl ether calorimetry	4
POMD	1	Molar enthalpy, kJ/mol ; Crystal 1	Temperature, K; Crystal 1	Pressure, kPa; Crystal 1	Crystal 1	Drop ice or diphenyl ether calorimetry	7
POMD	1	Molar enthalpy, kJ/mol ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Drop ice or diphenyl ether calorimetry	10
POMD	2	Normal melting temperature, K ; Crystal			Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	2	Molar enthalpy of transition or fusion, kJ/mol ; Crystal			Crystal Liquid Air at 1 atmosphere	Drop calorimetry	1
POMD	2	Molar heat capacity at constant pressure, J/K/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	DSC	124
POMD	2	Molar enthalpy, kJ/mol ; Crystal	Temperature, K; Crystal	Pressure, kPa; Crystal	Crystal	Drop ice or diphenyl ether calorimetry	8
POMD	2	Molar enthalpy, kJ/mol ; Liquid	Temperature, K; Liquid	Pressure, kPa; Liquid	Liquid	Drop ice or diphenyl ether calorimetry	6
POMD	3	Molar enthalpy, kJ/mol ; Glass	Temperature, K; Glass	Pressure, kPa; Glass	Glass	Drop calorimetry	9
POMD	3	Molar heat capacity at constant pressure, J/K/mol ; Glass	Temperature, K; Glass	Pressure, kPa; Glass	Glass	DSC	124

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Enthalpy and heat capacity of Na2MoO4 and CaMoO4

Sugawara, Toru, Jin, Kosuke

ABSTRACT