Barbituric acid

• Formula: C₄H₄N₂O₃
• Molecular weight: 128.0862
• IUPAC Standard InChI: InChI=1S/C4H4N2O3/c7-2-1-3(8)6-4(9)5-2/h1H2,(H2,5,6,7,8,9) Copy

  
• IUPAC Standard InChIKey: HNYOPLTXPVRDBG-UHFFFAOYSA-N Copy
• CAS Registry Number: 67-52-7
• Chemical structure:
  This structure is also available as a 2d Mol file
• Species with the same structure:
  • Barbituric acid
• Other names: 2,4,6(1H,3H,5H)-Pyrimidinetrione; Malonylurea; Pyrimidinetrione; Urea, N,N'-(1,3-dioxo-1,3-propanediyl)-; 2,4,6-Pyrimidinetriol; 2,4,6-Trihydroxypyrimidine; 2,4,6-Trioxohexahydropyrimidine; 6-Hydroxyuracil; 2,4,6-Pyrimidinetrione(1H,3H,5H)
• Information on this page:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
• 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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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 by: John E. Bartmess

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

C₄H₃N₂O₃^- +  =

By formula: C₄H₃N₂O₃^- + H⁺ = C₄H₄N₂O₃

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 compiled as indicated in comments:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi

Ionization energy determinations

De-protonation reactions

C₄H₃N₂O₃^- +  =

By formula: C₄H₃N₂O₃^- + H⁺ = C₄H₄N₂O₃

IR Spectrum

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Data compiled by: Coblentz Society, Inc.

• SOLID (SPLIT MULL); DOW KBr FOREPRISM-GRATING; DIGITIZED BY COBLENTZ SOCIETY (BATCH I) FROM HARD COPY
  2, 2 cm^-1 resolution

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

UV/Visible spectrum

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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: Victor Talrose, Alexander N. Yermakov, Alexy A. Usov, Antonina A. Goncharova, Axlexander N. Leskin, Natalia A. Messineva, Natalia V. Trusova, Margarita V. Efimkina

Spectrum

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Additional Data

References

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

Soldatova, Kabo, et al., 1990
Soldatova, T.V.; Kabo, G.Ya.; Kozyro, A.A.; Frenkel, M.L., Thermodynamic properties and tautomerism of barbituric acid, Russ. J. Phys. Chem. (Engl. Transl.), 1990, 64, 177-180. [all data]

Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P., Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A), Can. J. Chem., 1978, 56, 1. [all data]

Dougherty, Younathan, et al., 1978
Dougherty, D.; Younathan, E.S.; Voll, R.; Abdulnur, S.; McGlynn, S.P., Photoelectron spectroscopy of some biological molecules, J. Electron Spectrosc. Relat. Phenom., 1978, 13, 379. [all data]

Stimson, 1949
Stimson, M.M., J. Am. Chem. Soc., 1949, 71, 1470. [all data]

Notes

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• Symbols used in this document:
  

  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

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