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 Computational Chemistry Comparison and Benchmark DataBase Release 18 October 2016 NIST Standard Reference Database 101
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# Listing of experimental geometry data for C5H8(Cyclopentene)

## Rotational Constants (cm-1)

See section I.F.4 to change rotational constant units
A B C
0.24329 0.24107 0.13174
Rotational Constants from 1968Sch:3552
Calculated rotational constants for C5H8 (Cyclopentene).

## 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 1.085 4 10 1976Hellwege(II/7) !assumed, C has =
rCH 1.095 1 6 1976Hellwege(II/7) !assumed
rCC 1.540 1 2 1976Hellwege(II/7) !assumed
rCC 1.350 4 5 1976Hellwege(II/7) !assumed
rCC 1.518 2 4 1976Hellwege(II/7) one C has =
aHCH 109.5 6 1 7 1976Hellwege(II/7) !assumed
aCCC 106.3 2 1 3 1976Hellwege(II/7)
dCCCCCCC 22.3 1976Hellwege(II/7) angle between the CCC plane and the CC=CC plane

## 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 4
C=C 1

Atom x (Å) y (Å) z (Å)

Atom - Atom Distances (Å)

Calculated geometries for C5H8 (Cyclopentene).
References
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squib reference DOI
1968Sch:3552 LH Scharpen " Rotation-Vibration Interaction and Barrier to Ring Inversion in Cyclopentene" J. Chem. Phys. 48(8), 3552, 1968 10.1063/1.1669649
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.

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