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.1. (XV.A.)

Listing of experimental data for HCCF (Fluoroacetylene)

Other names
Ethyne, fluoro-; Fluoroethyne; Monofluoroacetylene; Acetylene, fluoro-;
State Conformation
1Σ C*V
Enthalpy of formation (Hfg), Entropy, Integrated heat capacity (0 K to 298.15 K) (HH), Heat Capacity (Cp)
Property Value Uncertainty units Reference Comment
Hfg(298.15K) enthalpy of formation 125.52   kJ mol-1 webbook
Hfg(0K) enthalpy of formation     kJ mol-1 webbook
Entropy (298.15K) entropy 231.61   J K-1 mol-1 webbook
Information can also be found for this species in the NIST Chemistry Webbook
Vibrational levels (cm-1) vibrations
Mode Number Symmetry Frequency (cm-1) Frequency Reference Intensity (km mol-1) Int. unc. Intensity Reference Comment
1 Σ+ 3355 webbook      
2 Σ+ 2255 webbook      
3 Σ+ 1055 webbook      
4 Π 578 webbook      
5 Π 367 webbook      

vibrational zero-point energy: 4277.5 cm-1
Calculated vibrational frequencies for HCCF (Fluoroacetylene).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
  0.32376 0.32376 1963Tyl/She:2661

Calculated rotational constants for HCCF (Fluoroacetylene).

Product of moments of inertia moments of inertia
52.06771amu Å2   8.646182E-39gm cm2
Geometric Data
picture of Fluoroacetylene

Point Group C∞v

Internal coordinates
distances (r) in Å, angles (a) in degrees, dihedrals (d) in degrees

Description Value unc. Connectivity Reference Comment
Atom 1 Atom 2 Atom 3 Atom 4
rCC 1.198 0.003 1 2 1976Hellwege(II/7)
rCF 1.279 0.005 1 3 1976Hellwege(II/7)
rCH 1.053 0.005 2 4 1976Hellwege(II/7)
aCCF 180 2 1 3 1976Hellwege(II/7)
aHCC 180 1 2 4 1976Hellwege(II/7)


Atom x (Å) y (Å) z (Å)
C1 0.0000 0.0000 -0.0942
C2 0.0000 0.0000 -1.2922
F3 0.0000 0.0000 1.1848
H4 0.0000 0.0000 -2.3452

Atom - Atom Distances bond lengths
Distances in Å

  C1 C2 F3 H4
C1   1.19801.27902.2510
C2 1.1980   2.47701.0530
F3 1.27902.4770   3.5300
H4 2.25101.05303.5300  

Calculated geometries for HCCF (Fluoroacetylene).

Experimental Bond Angles (degrees) from cartesians bond angles

atom1 atom2 atom3 angle         atom1 atom2 atom3 angle
C1 C2 H4 180.000 C2 C1 F3 180.000

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-F 1
H-C 1


Atom 1 Atom 2
C1 C2
C1 F3
C2 H4
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1   1Σ

Ionization Energies (eV)

Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
11.260       webbook
Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
Dipole (Debye) Reference comment
0.730 NSRDS-NBS10  

Calculated electric dipole moments for HCCF (Fluoroacetylene).
Electric quadrupole moment quadrupole
Quadrupole (D Å) Reference comment
xx yy zz
-1.980 -1.980 3.960 1971Fly/Ben:225 3.96 +- 0.14

Calculated electric quadrupole moments for HCCF (Fluoroacetylene).

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squib reference DOI
1971Fly/Ben:225 WH Flygare, RC Benson "The molecular Zeeman effect in diamagnetic molecules and the determination of molecular magnetic moments (g values), magnetic susceptibilities, and molecular quadrupole moments" Mol. Phys. 1971, 20 (2), 225-250 10.1080/00268977100100221
1976Hellwege(II/7) Hellwege, KH and AM Hellwege (ed.). Landolt-Bornstein: Group II: Atomic and Molecular Physics Volume 7: Structure Data of Free Polyatomic Molecules. Springer-Verlag. Berlin. 1976.  
NSRDS-NBS10 R. D. Nelson Jr., D. R. Lide, A. A. Maryott "Selected Values of electric dipole moments for molecules in the gas phase" NSRDS-NBS10, 1967  
webbook NIST Chemistry Webbook (  

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