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
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

NIST policy on privacy, security, and accessibility.

Please rate our products
© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to

return to home page

II.A.3. (XII.A.1.)

Listing of experimental geometry data for C3H4 (cyclopropene)

Rotational Constants (cm-1)

See section I.F.4 to change rotational constant units
1.00273 0.72803 0.46018
Rotational Constants from 1975Sti/Lau:1890
Calculated rotational constants for C3H4 (cyclopropene).

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 1.509 1 2 1975Sti/Lau:1890
rCC 1.296 2 3 1975Sti/Lau:1890
rCH 1.072 2 4 1975Sti/Lau:1890 ethylenic
rCH 1.088 1 6 1975Sti/Lau:1890 methylenic
aCCC 50.84 2 1 3 1975Sti/Lau:1890
aHCC 149.85 2 3 5 1975Sti/Lau:1890
aHCH 114.57 6 1 7 1975Sti/Lau:1890
aCCC 64.58 1 2 3 1975Sti/Lau:1890 by symmetry
aHCC 145.57 1 3 5 1975Sti/Lau:1890 by symmetry
aHCC 119.22 2 1 6 1975Sti/Lau:1890 by symmetry
picture of cyclopropene

Bond descriptions

Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
C-C 2
C=C 1
H-C 4

Atom x (Å) y (Å) z (Å)
C1 0.0000 0.0000 0.8628
C2 0.0000 0.6476 -0.5001
C3 0.0000 -0.6476 -0.5001
H4 0.0000 1.5745 -1.0386
H5 0.0000 -1.5745 -1.0386
H6 0.9154 0.0000 1.4509
H7 -0.9154 0.0000 1.4509

Atom - Atom Distances (Å)

  C1 C2 C3 H4 H5 H6 H7

Calculated geometries for C3H4 (cyclopropene).
By selecting the following links, you may be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to
squib reference DOI
1975Sti/Lau:1890 Stigliani, Laurie, Li, Microwave spectrum and structure of cyclopropene, J. of Chem. Phys, Vol. 62, #5, pgs. 1890-1892 10.1063/1.430674

Got a better number? Please email us at