The standard molar enthalpies of formation of xanthine and hypoxanthine were measured by using high-precision combustion calorimetry. The standard molar enthalpies of sublimation of these compounds at 298.15 K were derived by the quartz-crystal microbalance technique. Limited thermodynamic data available in the literature are compared with our new experimental data. In addition, we use the G4 method to calculate the molar enthalpies of formation of xanthine and hypoxanthine in the gas phase. There is good agreement between the evaluated experimental data and the quantum-chemical calculations.
Compounds
#
Formula
Name
1
CO2
carbon dioxide
2
N2
nitrogen
3
H2O
water
4
O2
oxygen
5
C5H4N4O2
3,7-dihydropurine-2,6-dione
6
C5H4N4O
1,7-dihydro-6H-purin-6-one
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
5
Molar enthalpy of vaporization or sublimation, kJ/mol ; Crystal
Temperature, K; Crystal
Crystal
Gas
Derived by Second law
1
POMD
6
Molar enthalpy of vaporization or sublimation, kJ/mol ; Crystal
Temperature, K; Crystal
Crystal
Gas
Derived by Second law
1
RXND
5
1
2
3
4
Specific internal energy of reaction at constant volume, J/g
Static bomb calorimetry
1
RXND
6
1
2
3
4
Specific internal energy of reaction at constant volume, J/g