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

Listing of experimental geometry data for CH3CCH (propyne)

Rotational Constants (cm-1)

See section I.F.4 to change rotational constant units
5.21000 0.28506 0.28506
Rotational Constants from 1966Herzberg
Calculated rotational constants for CH3CCH (propyne).

Point Group C3v

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
rCH 1.096 1 5 1973Dun/McK:232 CH3 end
rCH 1.060 3 4 1973Dun/McK:232 CH end
rCC 1.460 1 2 1973Dun/McK:232
rCC 1.207 2 3 1973Dun/McK:232
aHCH 108.28 5 1 6 1966Herzberg
aHCC 110.63 2 1 5 1973Dun/McK:232 from symmetry
picture of propyne

Bond descriptions

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

Atom x (Å) y (Å) z (Å)
C1 0.0000 0.0000 -1.2455
C2 0.0000 0.0000 0.2135
C3 0.0000 0.0000 1.4195
H4 0.0000 0.0000 2.4755
H5 0.0000 1.0465 -1.6003
H6 0.9063 -0.5232 -1.6003
H7 -0.9063 -0.5232 -1.6003

Atom - Atom Distances (Å)

  C1 C2 C3 H4 H5 H6 H7

Calculated geometries for CH3CCH (propyne).
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squib reference DOI
1966Herzberg Herzberg, G., Electronic spectra and electronic structure of polyatomic molecules,Van Nostrand,New York, 1966  
1973Dun/McK:232 JL Duncan, DC McKean, PD Mallinson, RD McCulloch " Infrared Spectra of CHD2Cl and CHD2CCH and the geometries of Methyl Chloride and Propyne" J. Mol. Spec. 46, 232-239, 1973 10.1016/0022-2852(73)90039-8

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