1,3-Cyclopentadiene

• Formula: C₅H₆
• Molecular weight: 66.1011
• IUPAC Standard InChI: InChI=1S/C5H6/c1-2-4-5-3-1/h1-4H,5H2 Copy

  
• IUPAC Standard InChIKey: ZSWFCLXCOIISFI-UHFFFAOYSA-N Copy
• CAS Registry Number: 542-92-7
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
  The 3d structure may be viewed using Java or Javascript.
• Other names: Cyclopentadiene; Pentole; Pyropentylene; R-Pentine
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • Gas Chromatography
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Ion clustering data
  • IR Spectrum
  • UV/Visible spectrum
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Gas Phase Kinetics Database
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Reaction thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
MS - José A. Martinho Simões

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

 +  =

By formula: C₅H₅^- + H⁺ = C₅H₆

 +  = ( • )

By formula: C₅H₅^- + C₅H₆ = (C₅H₅^- • C₅H₆)

Free energy of reaction

 +  =

By formula: C₄H₂O₃ + C₅H₆ = C₉H₈O₃

2 +  =

By formula: 2H₂ + C₅H₆ = C₅H₁₀

 +  = ( • )

By formula: Cl^- + C₅H₆ = (Cl^- • C₅H₆)

Free energy of reaction

 +  =

By formula: C₅H₆ + C₆N₄ = C₁₁H₆N₄

=  + 

By formula: C₇H₈ = C₅H₆ + C₂H₂

2 (l) +  (cr) =  (cr) +  (g)

By formula: 2C₅H₆ (l) + Mg (cr) = C₁₀H₁₀Mg (cr) + H₂ (g)

C₈H₆MoO₃ (solution) + 3 (solution) = C₁₈H₁₅MoN₃O₃ (solution) +  (solution)

By formula: C₈H₆MoO₃ (solution) + 3C₄H₄N₂ (solution) = C₁₈H₁₅MoN₃O₃ (solution) + C₅H₆ (solution)

=

By formula: C₅H₆ = C₅H₆

= 2

By formula: C₁₀H₁₂ = 2C₅H₆

2 +  =  + 

By formula: 2HI + C₅H₆ = C₅H₈ + I₂

=  + 

By formula: C₇H₁₀ = C₅H₆ + C₂H₄

=  + 

By formula: C₁₁H₆N₄ = C₅H₆ + C₆N₄

 +  =

By formula: C₅H₆ + C₂H₂ = C₇H₈

2 =

By formula: 2C₅H₆ = C₁₀H₁₂

2 = C₁₀H₁₂

By formula: 2C₅H₆ = C₁₀H₁₂

Gas phase ion energetics data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
MM - Michael M. Meot-Ner (Mautner)
LL - Sharon G. Lias and Joel F. Liebman
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₅H₆⁺ (ion structure unspecified)

Proton affinity at 298K

Gas basicity at 298K

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

 +  =

By formula: C₅H₅^- + H⁺ = C₅H₆

Mass spectrum (electron ionization)

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

Gas Chromatography

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Kovats' RI, non-polar column, isothermal

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Kovats' RI, non-polar column, custom temperature program

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Kovats' RI, polar column, isothermal

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Kovats' RI, polar column, temperature ramp

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Normal alkane RI, non-polar column, isothermal

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Normal alkane RI, non-polar column, temperature ramp

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Normal alkane RI, non-polar column, custom temperature program

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Lee's RI, non-polar column, temperature ramp

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References

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), Gas Chromatography, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

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Notes

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), Gas Chromatography, References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  T	Temperature
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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