National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 18October 2016
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
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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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II.A.3. (XII.A.1.)

Listing of experimental geometry data for C4H6 (Cyclobutene)

Rotational Constants (cm-1)

See section I.F.4 to change rotational constant units
0.43006 0.40782 0.22737
Rotational Constants from NISThydrocarbon
Calculated rotational constants for C4H6 (Cyclobutene).

Point Group C2v

Internal coordinates

(distances (r) in Å) (angles (a) in degrees) (dihedrals (d) in degrees)
Description Value Connectivity Reference Comment
Atom 1 Atom 2 Atom 3 Atom 4
rCC 1.342 1 2 1979Har/Lau:619
rCC 1.517 1 3 1979Har/Lau:619 =C to C
rCC 1.566 3 4 1979Har/Lau:619
rCH 1.083 1 5 1979Har/Lau:619 single H
rCH 1.094 3 7 1979Har/Lau:619 double H
aCCC 94.2 1 2 4 1979Har/Lau:619
aCCC 85.8 1 3 4 1979Har/Lau:619
aHCC 133.5 1 2 6 1979Har/Lau:619
aHCH 109.2 7 3 9 1979Har/Lau:619
aHCC 114.5 2 4 8 1979Har/Lau:619
picture of Cyclobutene

Bond descriptions

Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
C=C 1
C-C 3
H-C 6

Atom x (Å) y (Å) z (Å)
C1 0.0000 0.6710 0.8107
C2 0.0000 -0.6710 0.8107
C3 0.0000 0.7821 -0.7023
C4 0.0000 -0.7821 -0.7023
H5 0.0000 1.4165 1.5962
H6 0.0000 -1.4165 1.5962
H7 0.8986 1.2425 -1.1233
H8 -0.8986 -1.2425 -1.1233
H9 -0.8986 1.2425 -1.1233
H10 0.8986 -1.2425 -1.1233

Atom - Atom Distances (Å)

  C1 C2 C3 C4 H5 H6 H7 H8 H9 H10

Calculated geometries for C4H6 (Cyclobutene).
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squib reference DOI
1979Har/Lau:619 Harmony, Laurie, Kuczkowski,, Molecular structures of gas-phase polyatomic molecules determined by spectroscopic methods, J. of Phys. And Chem. Ref. Data, Vol. 8, #3, pgs. 619-722 10.1063/1.555605
NISThydrocarbon NIST Hydrocarbon spectral database (  

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