National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 22May 2022
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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New molecules in release22: NaAl, CH3CSNH2, C6H12O, C4H10O+, C6H6+, CH4-, ... more


The CCCBDB contains:
Experimental and computational thermochemical data for a selected set of 2186 gas-phase atoms and molecules.
Tools for comparing experimental and computational ideal-gas thermochemical properties.
Citation NIST Computational Chemistry Comparison and Benchmark Database
NIST Standard Reference Database Number 101
Release 22, May 2022, Editor: Russell D. Johnson III
A. Description and use
1. Detailed summary of the CCCBDB
Briefly, it consists of molecules with the following constraints:
  • Well-established heat of formation. This allows accurate thermochemical comparisons. However we have started adding calculations on ions, very few of which have thermochemical data.
  • Mostly atoms with atomic number less than 18 (Argon). Since release 11 we've added a few molecules with atoms from the K through Kr row (Ca, Sc, Ti, V, Cu, Zn, As, Se, and Br).
  • Mostly less than nine heavy atoms and twenty or fewer total atoms. The small size facilitates the use of common molecular orbital programs.
There are currently 2186 species in the CCCBDB, so not every molecule that meets the above criteria is included.
2. Using the CCCBDB
3. Index of properties in the CCCBDB
4. List showing how many calculations are currently in the CCCBDB
B.Species in the CCCBDB
1.All the species in the CCCBDB
2.Species and properties you would like in the CCCBDB
3.Links to all experimental and all calculated data for one species
4.List of recently added molecules.
5.A calculated geometry for a molecule.
To check whether or not a particular molecule is in the CCCBDB look at the "All experimental data for a given species" page in section II.A (experimental data section)
C.Viewing Options
1.Choose units
a.Energy: kJ/mol or kcal/mol
b.Bond length: Å, pm, or a0(bohr)
c.Rotational Constant: cm-1 or GHz
d.Dipole and quadrupole: Debye or e a0
e.Polarizability: a03 (bohr cubed) or Å3 (angstrom cubed)
f.Moment of inertia: amu Å2 or gm cm2
2.Omit some methods and basis sets
a.Omit some methods
b.Omit some basis sets
D.Information about quantum chemistry and thermochemistry
1.A glossary of computational terms.
2.A brief description of the thermochemical quantities and methods.