Acetic acid

• Formula: C₂H₄O₂
• Molecular weight: 60.0520
• IUPAC Standard InChI: InChI=1S/C2H4O2/c1-2(3)4/h1H3,(H,3,4) Copy

  
• IUPAC Standard InChIKey: QTBSBXVTEAMEQO-UHFFFAOYSA-N Copy
• CAS Registry Number: 64-19-7
• 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.
• Isotopologues:
  • Acetic acid-d4
• Other names: Ethanoic acid; Ethylic acid; Glacial acetic acid; Methanecarboxylic acid; Vinegar acid; CH3COOH; Acetasol; Acide acetique; Acido acetico; Azijnzuur; Essigsaeure; Octowy kwas; Acetic acid, glacial; Kyselina octova; UN 2789; Aci-jel; Shotgun; Ethanoic acid monomer; NSC 132953
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Gas phase ion energetics data
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • Vibrational and/or electronic energy levels
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 79
  • Henry's Law data
  • IR Spectrum
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
  • X-ray Photoelectron Spectroscopy Database, version 5.0
• Options:
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Gas phase 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:
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Constant pressure heat capacity of gas

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
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
LL - Sharon G. Lias and Joel F. Liebman

View reactions leading to C₂H₄O₂⁺ (ion structure unspecified)

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

 +  =

By formula: C₂H₃O₂^- + H⁺ = C₂H₄O₂

C₂H₃O₂^- +  =

By formula: C₂H₃O₂^- + H⁺ = C₂H₄O₂

Ion clustering 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:
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
B - John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

CH₆N⁺ +  = (CH₆N⁺ • )

By formula: CH₆N⁺ + C₂H₄O₂ = (CH₆N⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type NH+-O between organics

Free energy of reaction

CO₃^- +  = C₃H₄O₅^-

By formula: CO₃^- + C₂H₄O₂ = C₃H₄O₅^-

 +  = ( • )

By formula: C₂H₃O₂^- + C₂H₄O₂ = (C₂H₃O₂^- • C₂H₄O₂)

( • ) +  = ( • 2)

By formula: (C₂H₃O₂^- • C₂H₄O₂) + C₂H₄O₂ = (C₂H₃O₂^- • 2C₂H₄O₂)

( • 2) +  = ( • 3)

By formula: (C₂H₃O₂^- • 2C₂H₄O₂) + C₂H₄O₂ = (C₂H₃O₂^- • 3C₂H₄O₂)

( •  • ) +  = ( • 2 • )

By formula: (C₂H₃O₂^- • C₂H₄O₂ • H₂O) + C₂H₄O₂ = (C₂H₃O₂^- • 2C₂H₄O₂ • H₂O)

( • 2 • ) +  = ( • 3 • )

By formula: (C₂H₃O₂^- • 2C₂H₄O₂ • H₂O) + C₂H₄O₂ = (C₂H₃O₂^- • 3C₂H₄O₂ • H₂O)

( • ) +  = ( •  • )

By formula: (C₂H₃O₂^- • H₂O) + C₂H₄O₂ = (C₂H₃O₂^- • C₂H₄O₂ • H₂O)

C₂H₄NO₅^- +  +  = C₂H₆NO₆^-

By formula: C₂H₄NO₅^- + H₂O + C₂H₄O₂ = C₂H₆NO₆^-

C₂H₅O⁺ +  = (C₂H₅O⁺ • )

By formula: C₂H₅O⁺ + C₂H₄O₂ = (C₂H₅O⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

(C₂H₅O⁺ • ) +  = (C₂H₅O⁺ • 2)

By formula: (C₂H₅O⁺ • C₂H₄O₂) + C₂H₄O₂ = (C₂H₅O⁺ • 2C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

(C₂H₅O⁺ • 2) +  = (C₂H₅O⁺ • 3)

By formula: (C₂H₅O⁺ • 2C₂H₄O₂) + C₂H₄O₂ = (C₂H₅O⁺ • 3C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

(C₂H₅O⁺ • 3) +  = (C₂H₅O⁺ • 4)

By formula: (C₂H₅O⁺ • 3C₂H₄O₂) + C₂H₄O₂ = (C₂H₅O⁺ • 4C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

Free energy of reaction

C₂H₇O⁺ +  = (C₂H₇O⁺ • )

By formula: C₂H₇O⁺ + C₂H₄O₂ = (C₂H₇O⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

C₃H₄O₅^- +  +  = C₃H₆O₆^-

By formula: C₃H₄O₅^- + H₂O + C₂H₄O₂ = C₃H₆O₆^-

C₄H₁₀NO⁺ +  = (C₄H₁₀NO⁺ • )

By formula: C₄H₁₀NO⁺ + C₂H₄O₂ = (C₄H₁₀NO⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds of the type OH-O between organics

C₆H₅NO₂^- +  = (C₆H₅NO₂^- • )

By formula: C₆H₅NO₂^- + C₂H₄O₂ = (C₆H₅NO₂^- • C₂H₄O₂)

 +  = ( • )

By formula: C₆H₅O^- + C₂H₄O₂ = (C₆H₅O^- • C₂H₄O₂)

 +  = ( • )

By formula: C₆H₅S^- + C₂H₄O₂ = (C₆H₅S^- • C₂H₄O₂)

 +  = C₈H₉O₂S^-

By formula: C₆H₅S^- + C₂H₄O₂ = C₈H₉O₂S^-

C₆H₁₂NO₃⁺ +  = (C₆H₁₂NO₃⁺ • )

By formula: C₆H₁₂NO₃⁺ + C₂H₄O₂ = (C₆H₁₂NO₃⁺ • C₂H₄O₂)

Bond type: Hydrogen bonds with polydentate bonding in positive ions

 +  = ( • )

By formula: Cl^- + C₂H₄O₂ = (Cl^- • C₂H₄O₂)

 +  = ( • )

By formula: F^- + C₂H₄O₂ = (F^- • C₂H₄O₂)

 +  = ( • )

By formula: I^- + C₂H₄O₂ = (I^- • C₂H₄O₂)

 +  = ( • )

By formula: Li⁺ + C₂H₄O₂ = (Li⁺ • C₂H₄O₂)

 +  = C₂H₄NO₄^-

By formula: NO₂^- + C₂H₄O₂ = C₂H₄NO₄^-

 +  = C₂H₄NO₅^-

By formula: NO₃^- + C₂H₄O₂ = C₂H₄NO₅^-

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

Vibrational and/or electronic energy levels

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References, Notes

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

Data compiled by: Takehiko Shimanouchi

Symmetry:   C_s     Symmetry Number σ = 1

Source: Shimanouchi, 1972

Notes

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Vibrational and/or electronic energy levels, 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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Staley, R.H.; Beauchamp, J.L., Intrinsic Acid - Base Properties of Molecules. Binding Energies of Li+ to pi - and n - Donor Bases, J. Am. Chem. Soc., 1975, 97, 20, 5920, https://doi.org/10.1021/ja00853a050 . [all data]

Dzidic and Kebarle, 1970
Dzidic, I.; Kebarle, P., Hydration of the Alkali Ions in the Gas Phase. Enthalpies and Entropies of Reactions M+(H2O)n-1 + H2O = M+(H2O)n, J. Phys. Chem., 1970, 74, 7, 1466, https://doi.org/10.1021/j100702a013 . [all data]

Shimanouchi, 1972
Shimanouchi, T., Tables of Molecular Vibrational Frequencies Consolidated Volume I, National Bureau of Standards, 1972, 1-160. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Vibrational and/or electronic energy levels, References

• Symbols used in this document:
  

  AE	Appearance energy
  Cp,gas	Constant pressure heat capacity of gas
  IE (evaluated)	Recommended ionization energy
  S°gas	Entropy of gas at standard conditions
  T	Temperature
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  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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