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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Tautomer energy comparison

using model chemistry: PBEPBE/6-311+G(3df,2p)

formula sketch Energy (kJ mol-1) Name difference
A B calculated experiment A B
C3H4 sketch of allene sketch of propyne -14 7 allene propyne -21
C4H6 sketch of 1,2-Butadiene sketch of 1,3-Butadiene 39 51 1,2-Butadiene 1,3-Butadiene -12
C4H6 sketch of 1,2-Butadiene sketch of 2-Butyne 4 17 1,2-Butadiene 2-Butyne -12
C4H6 sketch of Cyclobutene sketch of 1,3-Butadiene 47 49 Cyclobutene 1,3-Butadiene -2
C4H6 sketch of 1-Methylcyclopropene sketch of 1,2-Butadiene 75 82 1-Methylcyclopropene 1,2-Butadiene -7
C4H6 sketch of Methylenecyclopropane sketch of 1-Methylcyclopropene -47 -42 Methylenecyclopropane 1-Methylcyclopropene -6
C3H4O2 sketch of 2-Propenoic acid sketch of β–Propiolactone -26 -29 2-Propenoic acid β–Propiolactone 3
C4H6S sketch of Thiophene, 2,5-dihydro- sketch of Thiophene, 2,3-dihydro- 4 -4 Thiophene, 2,5-dihydro- Thiophene, 2,3-dihydro- 9
C5H8 sketch of 1,3-Pentadiene, (E)- sketch of 1,4-Pentadiene -38 -25 1,3-Pentadiene, (E)- 1,4-Pentadiene -12
C5H8 sketch of 1,3-Pentadiene, (E)- sketch of 1,2-Pentadiene -57 -64 1,3-Pentadiene, (E)- 1,2-Pentadiene 7
C5H8 sketch of 1,2-Butadiene, 3-methyl- sketch of 1,3-Butadiene, 2-methyl- 39 52 1,2-Butadiene, 3-methyl- 1,3-Butadiene, 2-methyl- -13
C4H8O sketch of Butanal sketch of Furan, tetrahydro- -31 -29 Butanal Furan, tetrahydro- -2
C5H10 sketch of 1-Butene, 2-methyl- sketch of 2-Butene, 2-methyl- 13 5 1-Butene, 2-methyl- 2-Butene, 2-methyl- 7
C5H10 sketch of Cyclopropane, 1,1-dimethyl- sketch of 1-Butene, 2-methyl- 19 29 Cyclopropane, 1,1-dimethyl- 1-Butene, 2-methyl- -10
C6H8 sketch of 1,4-Cyclohexadiene sketch of 1,3-Cyclohexadiene 1 3 1,4-Cyclohexadiene 1,3-Cyclohexadiene -1