Carbon monoxide

• Formula: CO
• Molecular weight: 28.0101
• IUPAC Standard InChI: InChI=1S/CO/c1-2 Copy

  
• IUPAC Standard InChIKey: UGFAIRIUMAVXCW-UHFFFAOYSA-N Copy
• CAS Registry Number: 630-08-0
• 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: Carbon oxide (CO); CO; Exhaust gas; Flue gas; Carbonic oxide; Carbon oxide; Carbone (oxyde de); Carbonio (ossido di); Kohlenmonoxid; Kohlenoxyd; Koolmonoxyde; NA 9202; Oxyde de carbone; UN 1016; Wegla tlenek; Carbon monooxide
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• Information on this page:
  • Gas phase thermochemistry data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Phase change data
  • Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 100, reactions 101 to 150, reactions 151 to 200, reactions 201 to 249
  • Henry's Law data
  • Ion clustering data
  • IR Spectrum
  • Constants of diatomic molecules
  • Fluid Properties
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Electron-Impact Ionization Cross Sections (on physics web site)
  • Gas Phase Kinetics Database
• Options:
  • Switch to SI units

Data at NIST subscription sites:

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

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Gas phase thermochemistry data

Go To: Top, Gas phase ion energetics 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.

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
    C_p = heat capacity (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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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:
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
B - John E. Bartmess

View reactions leading to CO⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

Appearance energy determinations

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, 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: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

References

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

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

Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A., CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Refaey and Franklin, 1976
Refaey, K.M.A.; Franklin, J.L., Endoergic ion-molecule-collision processes of negative ions. III. Collisions of I- on O₂, CO and CO₂, Int. J. Mass Spectrom. Ion Phys., 1976, 20, 19. [all data]

Erman, Karawajczyk, et al., 1993
Erman, P.; Karawajczyk, A.; Rachlew-Kallne, E.; Stromholm, C.; Larsson, J.; Persson, A.; Zerne, R., Direct determination of the ionization potential of CO by resonantly enhanced multiphoton ionization mass spectrometry, Chem. Phys. Lett., 1993, 215, 173. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Fock, Gurtler, et al., 1980
Fock, J.-H.; Gurtler, P.; Koch, E.E., Molecular Rydberg transitions in carbon monoxide: term value/ionization energy correlation of BF, CO and N₂., Chem. Phys., 1980, 47, 87. [all data]

Hille and Mark, 1978
Hille, E.; Mark, T.D., Cross section for single and double ionization of carbon monoxide by electron impact from threshold up to 180 eV, J. Chem. Phys., 1978, 69, 4600. [all data]

Rabalais, Debies, et al., 1974
Rabalais, J.W.; Debies, T.P.; Berkosky, J.L.; Huang, J.-T.J.; Ellison, F.O., Calculated photoionization cross sections relative experimental photoionization intensities for a selection of small molecules, J. Chem. Phys., 1974, 61, 516. [all data]

Natalis, 1973
Natalis, P., Contribution a la spectroscopie photoelectronique. Effets de l'autoionisation dans less spectres photoelectroniques de molecules diatomiques et triatomiques, Acad. R. Belg. Mem. Cl. Sci. Collect. 8, 1973, 41, 1. [all data]

Ogawa and Ogawa, 1972
Ogawa, M.; Ogawa, S., Absorption spectrum of CO in the Hopfield helium continuum region, 600-1020 A, J. Mol. Spectrosc., 1972, 41, 393. [all data]

Hotop and Niehaus, 1970
Hotop, H.; Niehaus, A., Reactions of excited atoms and molecules with atoms and molecules. V.Comparison of Penning electron and photoelectron spectra of H₂, N₂ and CO, Intern. J. Mass Spectrom. Ion Phys., 1970, 5, 415. [all data]

Collin and Natalis, 1969
Collin, J.E.; Natalis, P., Ionic states and photon impact-enhanced vibrational excitation in diatomic molecules by photoelectron spectroscopy. Photoelectron spectra of N₂, CO and O₂, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 231. [all data]

Turner and May, 1966
Turner, D.W.; May, D.P., Franck-Condon factors in ionization: experimental measurement using molecular photoelectron spectroscopy, J. Chem. Phys., 1966, 45, 471. [all data]

Krupenie, 1966
Krupenie, P.H., The band spectrum of carbon monoxide, Natl. Stand. Ref. Data Ser., Natl. Bur. Stand. NSRDS-NBS, 1966, 5. [all data]

Cook, Metzger, et al., 1965
Cook, G.R.; Metzger, P.H.; Ogawa, M., Photoionization and absorption coefficients of CO in the 600 to 1000 A region, Can. J. Phys., 1965, 43, 1706. [all data]

Potts and Williams, 1974
Potts, A.W.; Williams, T.A., The observation of "forbidden" transitions in He II photoelectron spectra, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 3. [all data]

Katrib, Debies, et al., 1973
Katrib, A.; Debies, T.P.; Colton, R.J.; Lee, T.H.; Rabalais, J.W., The use of differential photoionization cross sections as a function of excitation energy in assigning photoelectron spectra, Chem. Phys. Lett., 1973, 22, 196. [all data]

Thomas, 1970
Thomas, T.D., X-ray photoelectron spectroscopy of carbon monoxide, J. Chem. Phys., 1970, 53, 1744. [all data]

Oertel, Schenk, et al., 1980
Oertel, H.; Schenk, H.; Baumgartel, H., Ion pair formation from photon irradiation of O₂, NO and CO in 17-30 eV, Chem. Phys., 1980, 46, 251. [all data]

Smyth, Schiavone, et al., 1974
Smyth, K.C.; Schiavone, J.A.; Freund, R.S., Dissociative excitation of CO by electron impact: Translational spectroscopy of long-lived high-Rydberg fragment atoms, J. Chem. Phys., 1974, 60, 1358. [all data]

Locht and Momigny, 1971
Locht, R.; Momigny, J., Mass spectrometric study of ion-pair processes in diatomic molecules: H₂, CO, NO and O₂, Int. J. Mass Spectrom. Ion Phys., 1971, 7, 121. [all data]

Hierl and Franklin, 1967
Hierl, P.M.; Franklin, J.L., Appearance potentials and kinetic energies of ions from N₂, CO, and NO, J. Chem. Phys., 1967, 47, 3154. [all data]

Fineman and Petrocelli, 1961
Fineman, M.A.; Petrocelli, A.W., Molecular studies with a Lozier electron impact apparatus, Planetary Space Sci., 1961, 3, 187. [all data]

Weissler, Samson, et al., 1959
Weissler, G.L.; Samson, J.A.R.; Ogawa, M.; Cook, G.R., Photoionization analysis by mass spectroscopy, J. Opt. Soc. Am., 1959, 49, 338. [all data]

Notes

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

• Symbols used in this document:
  

  AE	Appearance energy
  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  ΔfH(+) ion,0K	Enthalpy of formation of positive ion at 0K
  ΔfH°gas	Enthalpy of formation of gas at standard conditions

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