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Experimental data for C3H4 (cyclopropene)

22 02 02 11 45
Other names
Cyclopropene;
INChI INChIKey SMILES IUPAC name
InChI=1S/C3H4/c1-2-3-1/h1-2H,3H2 OOXWYYGXTJLWHA-UHFFFAOYSA-N C1=CC1 Cyclopropene
State Conformation
1A1 C2v
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 277.00 3.00 kJ mol-1 TRC
Hfg(0K) enthalpy of formation 285.80 3.00 kJ mol-1 TRC
Entropy (298.15K) entropy 243.60   J K-1 mol-1 TRC
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity     kJ mol-1  
Heat Capacity (298.15K) heat capacity 52.90   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 Intensity Comment Description
Fundamental(cm-1) Harmonic(cm-1) Reference (km mol-1) unc. Reference
1 A1 3158   1987Cra/Pra:1764      
2 A1 2909   1987Cra/Pra:1764      
3 A1 1653   1987Cra/Pra:1764      
4 A1 1483   1987Cra/Pra:1764      
5 A1 1110   1987Cra/Pra:1764      
6 A1 905   1987Cra/Pra:1764      
7 A2 996   1987Cra/Pra:1764      
8 A2 820   1987Cra/Pra:1764      
9 B1 2995   1987Cra/Pra:1764      
10 B1 1088   1987Cra/Pra:1764      
11 B1 569   1987Cra/Pra:1764      
12 B2 3124   1987Cra/Pra:1764      
13 B2 1043   1987Cra/Pra:1764      
14 B2 1011   1987Cra/Pra:1764      
15 B2 769   1987Cra/Pra:1764      

vibrational zero-point energy: 11816.5 cm-1 (from fundamental vibrations)
Calculated vibrational frequencies for C3H4 (cyclopropene).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
1.00273 0.72803 0.46018 1975Sti/Lau:1890

Calculated rotational constants for C3H4 (cyclopropene).
Product of moments of inertia moments of inertia
14260.32amu3Å6   6.52976253085781E-116gm3 cm6
Geometric Data
picture of cyclopropene

Point Group C2v


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 1.509   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

Cartesians
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 bond lengths
Distances in Å
  C1 C2 C3 H4 H5 H6 H7
C1   1.50901.50902.46882.46881.08801.0880
C2 1.5090   1.29521.07202.28652.25032.2503
C3 1.50901.2952   2.28651.07202.25032.2503
H4 2.46881.07202.2865   3.14913.08463.0846
H5 2.46882.28651.07203.1491   3.08463.0846
H6 1.08802.25032.25033.08463.0846   1.8308
H7 1.08802.25032.25033.08463.08461.8308  

Calculated geometries for C3H4 (cyclopropene).

Experimental Bond Angles (degrees) from cartesians bond angles

atom1 atom2 atom3 angle         atom1 atom2 atom3 angle
C1 C2 C3 64.585 C1 C2 H4 145.570
C1 C3 C2 64.585 C1 C3 H5 145.570
C2 C1 C3 50.830 C2 C1 H6 119.219
C2 C1 H7 119.219 C2 C3 H5 149.845
C3 C1 H6 119.219 C3 C1 H7 119.219
C3 C2 H4 149.845 H6 C1 H7 114.570

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

Connectivity
Atom 1 Atom 2
C1 C2
C1 C3
C1 H6
C1 H7
C2 C3
C2 H4
C3 H5
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1   1A1

Ionization Energies (eV)
Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
9.670 0.010 9.860   webbook

Proton Affinity (kJ mol-1)
Proton Affinity unc. Product reference comment
818.5   C3H5+ webbook  
Dipole, Quadrupole and Polarizability
Electric dipole moment dipole
State Config State description Conf description Exp. min. Dipole (Debye) Reference comment Point Group Components
x y z total dipole quadrupole
1 1 1A1 C2v True       0.454 1959Kas/Mye:512-516 MW +-0.01 C2v 1 2
Experimental dipole measurement abbreviations: MW microwave; DT Dielectric with Temperature variation; DR Indirect (usually an upper limit); MB Molecular beam
Calculated electric dipole moments for C3H4 (cyclopropene).
Electric quadrupole moment quadrupole
State Config State description Conf description Exp. min. Quadrupole (D Å) Reference comment Point Group Components
xx yy zz dipole quadrupole
1 1 1A1 C2v True -2.000 2.400 -0.400 1971Fly/Ben:225 Qxx=-0.4+-0.4, Qyy=2.4+-0.3, Qzz=-2.0+-0.6 C2v 1 2

Calculated electric quadrupole moments for C3H4 (cyclopropene).

References
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squib reference DOI
1959Kas/Mye:512-516 PH Kasai, RJ Myers, DF Eggers, KB Wiberg "Microwave Spectrum, Structure, and Dipole Moment of Cyclopropene" J. Chem. Phys. 30, 512 (1959) 10.1063/1.1729978
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
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
1987Cra/Pra:1764 NC Craig, J Pranata, An Empirical Potential function for cyclopropene and Vibrational spectra of cycloproene-1,3-d2, J. Phys. Chem. 91(7), 1764, 1987 10.1021/j100291a018
TRC Frenkel, M; Marsh, K.N.; Wilhoit, R.C.; Kabo, G.J.; Roganov, G.N.,Thermodynamics of Organic Compounds in the Gas State,Thermodynamics Research Center, College Station, TX, 1994  
webbook NIST Chemistry Webbook (http://webbook.nist.gov/chemistry) 10.18434/T4D303

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