National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
VIITutorials and Units
VIIILinks to other sites
XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

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Enthalpy of formation from a reaction.

This form will calculate the enthalpy of formation of a species using ab initio results and experimental enthalpies of formation. Fill in the blanks with the appropriate information from your calculations. To clear the input boxes press the clear button at the bottom of the form. The descriptor is used for you to identify the species. It is not used in the calculations. The count is the quantity of a given species. Use it to balance the reaction. The electronic energies are from your ab initio calculation.
The value in the experimental row for reactant 1 is the predicted enthalpy of formation using the calculated values entered for all species and the experimental values for the other species.

Enthalpy of formation predictor form.

  Reactant 1 Reactant 2 Product 1 Product 2  
Count Total
Electronic Energy (hartrees) -0.047673
Vibrational zero point energy (cm-1) -996.6
Total energy (hartrees) -475.727611 0.000000 -40.151962 -435.627863 -0.052214
Total enthalpy (kJ mol-1)   -137.1
Experimental values of enthalpy of formation at 0K (zero Kelvin) in kJ mol-1


Reaction: 2 CH2F2 => CH4 + CF4
The example values (for the reaction 2 CH2F2 => CH4 + CF4) will be displayed if the descriptor for reactant 1 is left blank and the recalculate button is pressed, or press clear twice.