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
  • Phase change data
  • Gas phase ion energetics data
  • IR Spectrum
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
• Options:
  • Switch to SI units

Data at NIST subscription sites:

• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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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

Phase change 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: William E. Acree, Jr., James S. Chickos

Enthalpy of sublimation

Enthalpy of fusion

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

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics data, IR Spectrum, Notes

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]

Brunetti and Piacente, 1999
Brunetti, B.; Piacente, V., Sublimation Enthalpies Study for Barbituric, Tiobarbituric, and Selenobarbituric Acids from Their Vapor Pressure Measurements, J. Chem. Eng. Data, 1999, 44, 4, 809-812, https://doi.org/10.1021/je980300k . [all data]

Zielenkiewicz, Perlovich, et al., 1999
Zielenkiewicz, X.; Perlovich, G.L.; Wszelaka-Rylik, M., Journal of Thermal Analysis and Calorimetry, 1999, 57, 1, 225-234, https://doi.org/10.1023/A:1010179814511 . [all data]

Soldatova, Kabo, et al., 1990, 2
Soldatova, T.V.; Kabo, G.Ya.; Kozyro, A.A.; Frenkel, M.L., Thermodynamic properties and tautomerism of barbituric acid, Zh. Fiz. Khim., 1990, 64, 2, 336. [all data]

Roux, Temprado, et al., 2008
Roux, Maria Victoria; Temprado, Manuel; Notario, Rafael; Foces-Foces, Concepcion; Emel'yanenko, Vladimir N.; Verevkin, Sergey P., Structure-Energy Relationship in Barbituric Acid: A Calorimetric, Computational, and Crystallographic Study, J. Phys. Chem. A, 2008, 112, 32, 7455-7465, https://doi.org/10.1021/jp803370u . [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]

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]

Notes

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• Symbols used in this document:
  

  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfusH	Enthalpy of fusion
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔsubH	Enthalpy of sublimation

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