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Experimental data for C5H8 (Bicyclo[2.1.0]pentane)

22 02 02 11 45
Other names
Bicyclo[2.1.0]pentane;
INChI INChIKey SMILES IUPAC name
InChI=1S/C5H8/c1-2-5-3-4(1)5/h4-5H,1-3H2 MHLPKAGDPWUOOT-UHFFFAOYSA-N [C@@H]12CC[C@@H]1C2 Bicyclo[2.1.0]pentane
State Conformation
1A' CS
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 157.74   kJ mol-1 1991Rot/Ada:2499
Hfg(0K) enthalpy of formation     kJ mol-1 1991Rot/Ada:2499
Entropy (298.15K) entropy     J K-1 mol-1  
Integrated Heat Capacity (0 to 298.15K) integrated heat capacity     kJ mol-1  
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 A' 3072   1974Ale:1920      
2 A' 2994   1974Ale:1920      
3 A' 2982   1974Ale:1920      
4 A' 2946   1974Ale:1920      
5 A' 2874   1974Ale:1920      
6 A' 1469   1974Ale:1920      
7 A' 1445   1974Ale:1920      
8 A' 1330   1974Ale:1920      
9 A' 1298   1974Ale:1920      
10 A' 1213   1974Ale:1920      
11 A' 1190   1974Ale:1920      
12 A' 1105   1974Ale:1920      
13 A' 1109   1974Ale:1920      
14 A' 967   1974Ale:1920      
15 A' 914   1974Ale:1920      
16 A' 882   1974Ale:1920      
17 A' 774   1974Ale:1920      
18 A' 417   1974Ale:1920      
19 A" 3056   1974Ale:1920      
20 A"            
21 A" 2936   1974Ale:1920      
22 A" 1438   1974Ale:1920      
23 A" 1273   1974Ale:1920      
24 A" 1234   1974Ale:1920      
25 A" 1171   1974Ale:1920      
26 A" 1051   1974Ale:1920      
27 A" 1027   1974Ale:1920      
28 A" 977   1974Ale:1920      
29 A" 821   1974Ale:1920      
30 A" 879   1974Ale:1920      
31 A" 786   1974Ale:1920      
32 A" 758   1974Ale:1920      
33 A" 276   1974Ale:1920      

vibrational zero-point energy: 23332.0 cm-1 (from fundamental vibrations)
Calculated vibrational frequencies for C5H8 (Bicyclo[2.1.0]pentane).
Rotational Constants (cm-1) rotational constants
See section I.F.4 to change rotational constant units
A B C reference comment
0.30357 0.20394 0.15950 NISThydrocarbon

Calculated rotational constants for C5H8 (Bicyclo[2.1.0]pentane).
Product of moments of inertia moments of inertia
485136.1amu3Å6   2.22142458947062E-114gm3 cm6
Geometric Data
picture of Bicyclo[2.1.0]pentane

Point Group Cs


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 1.536   1 5 1976Hellwege(II/7) to tri
rCC 1.565   3 4 1976Hellwege(II/7) edge opp tri
rCC 1.528   1 3 1976Hellwege(II/7) from tri
rCC 1.507   1 2 1976Hellwege(II/7) tri
rCH 1.085   1 6 1976Hellwege(II/7) !assumed, at connection
rCH 1.095   3 8 1976Hellwege(II/7) !assumed, square
rCH 1.095   5 12 1976Hellwege(II/7) !assumed, tri
aHCH 115 12 5 13 1976Hellwege(II/7) !assumed, in tri
aHCH 108 8 3 10 1976Hellwege(II/7) !assumed, in square

These cartesians were determined using some assumed coordinate values. Cartesians
Atom x (Å) y (Å) z (Å)

Atom - Atom Distances bond lengths
Distances in Å
 

Calculated geometries for C5H8 (Bicyclo[2.1.0]pentane).

Bond descriptions


Examples: C-C single bond, C=C, double bond, C#C triple bond, C:C aromatic bond
Bond Type Count
H-C 8
C-C 6

Connectivity
Atom 1 Atom 2
C1 C2
C1 C3
C1 C5
C1 H6
C2 C4
C2 C5
C2 H7
C3 C4
C3 H8
C3 H10
C4 H9
C4 H11
C5 H12
C5 H13
Electronic energy levels (cm-1)
Energy (cm-1) Degeneracy reference description
0 1   1A'

Ionization Energies (eV)
Ionization Energy I.E. unc. vertical I.E. v.I.E. unc. reference
8.700 0.100 9.500 0.100 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 1A' Cs True 0.260 0.000   0.260 NISThydrocarbon x=c Cs 2 3
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 C5H8 (Bicyclo[2.1.0]pentane).
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 1A' Cs True       Cs 2 3

Calculated electric quadrupole moments for C5H8 (Bicyclo[2.1.0]pentane).
References
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squib reference DOI
1974Ale:1920 Aleksanyan. Vibrational spectra and structure of bicyclo[2.1.0]pentane. Bulletin of the Academy of Sciences of the USSR: Division of Chemical Science. Vol. 23. #9. pgs. 1920-1923. 10.1007/BF00922788
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.  
1991Rot/Ada:2499 WR Roth, O Adamczak, R. Breuckmann, H-W Lennartz, R Boese, "Die Berechnung von Resonanzenergien; das MM2ERW-Kraftfeld" Chem. Ber. 124 (1991) 2499-2521 10.1002/cber.19911241121
NISThydrocarbon NIST Hydrocarbon spectral database (http://www.physics.nist.gov/PhysRefData/MolSpec/Hydro/index.html) 10.18434/T4PC70
webbook NIST Chemistry Webbook (http://webbook.nist.gov/chemistry) 10.18434/T4D303

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