Methane

• Formula: CH₄
• Molecular weight: 16.0425
• IUPAC Standard InChI: InChI=1S/CH4/h1H4 Copy

  
• IUPAC Standard InChIKey: VNWKTOKETHGBQD-UHFFFAOYSA-N Copy
• CAS Registry Number: 74-82-8
• 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: Marsh gas; Methyl hydride; CH4; Fire Damp; R 50; Biogas; R 50 (refrigerant)
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Henry's Law data
  • Gas phase ion energetics data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Vibrational and/or electronic energy levels
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 100, reactions 101 to 112
  • Fluid Properties
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Electron-Impact Ionization Cross Sections (on physics web site)
  • Computational Chemistry Comparison and Benchmark Database
  • Gas Phase Kinetics Database
• Options:
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Henry's Law 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: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

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

View reactions leading to CH₄⁺ (ion structure unspecified)

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

CH₃^- +  =

By formula: CH₃^- + H⁺ = CH₄

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:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
RCD - Robert C. Dunbar

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

 +  = CH₄Br^-

By formula: Br^- + CH₄ = CH₄Br^-

 +  = ( • )

By formula: CF₃⁺ + CH₄ = (CF₃⁺ • CH₄)

CH₄Cl^- + 2 = C₂H₈Cl^-

By formula: CH₄Cl^- + 2CH₄ = C₂H₈Cl^-

CH₄F^- + 2 = C₂H₈F^-

By formula: CH₄F^- + 2CH₄ = C₂H₈F^-

CH₅⁺ +  = (CH₅⁺ • )

By formula: CH₅⁺ + CH₄ = (CH₅⁺ • CH₄)

(CH₅⁺ • ) +  = (CH₅⁺ • 2)

By formula: (CH₅⁺ • CH₄) + CH₄ = (CH₅⁺ • 2CH₄)

(CH₅⁺ • 2) +  = (CH₅⁺ • 3)

By formula: (CH₅⁺ • 2CH₄) + CH₄ = (CH₅⁺ • 3CH₄)

(CH₅⁺ • 3) +  = (CH₅⁺ • 4)

By formula: (CH₅⁺ • 3CH₄) + CH₄ = (CH₅⁺ • 4CH₄)

(CH₅⁺ • 4) +  = (CH₅⁺ • 5)

By formula: (CH₅⁺ • 4CH₄) + CH₄ = (CH₅⁺ • 5CH₄)

(CH₅⁺ • 5) +  = (CH₅⁺ • 6)

By formula: (CH₅⁺ • 5CH₄) + CH₄ = (CH₅⁺ • 6CH₄)

(CH₅⁺ • 6) +  = (CH₅⁺ • 7)

By formula: (CH₅⁺ • 6CH₄) + CH₄ = (CH₅⁺ • 7CH₄)

(CH₅⁺ • 7) +  = (CH₅⁺ • 8)

By formula: (CH₅⁺ • 7CH₄) + CH₄ = (CH₅⁺ • 8CH₄)

(CH₅⁺ • 8) +  = (CH₅⁺ • 9)

By formula: (CH₅⁺ • 8CH₄) + CH₄ = (CH₅⁺ • 9CH₄)

C₂H₅⁺ +  = (C₂H₅⁺ • )

By formula: C₂H₅⁺ + CH₄ = (C₂H₅⁺ • CH₄)

(C₂H₅⁺ • ) +  = (C₂H₅⁺ • 2)

By formula: (C₂H₅⁺ • CH₄) + CH₄ = (C₂H₅⁺ • 2CH₄)

(C₂H₅⁺ • 2) +  = (C₂H₅⁺ • 3)

By formula: (C₂H₅⁺ • 2CH₄) + CH₄ = (C₂H₅⁺ • 3CH₄)

(C₂H₅⁺ • 3) +  = (C₂H₅⁺ • 4)

By formula: (C₂H₅⁺ • 3CH₄) + CH₄ = (C₂H₅⁺ • 4CH₄)

(C₂H₅⁺ • 4) +  = (C₂H₅⁺ • 5)

By formula: (C₂H₅⁺ • 4CH₄) + CH₄ = (C₂H₅⁺ • 5CH₄)

(C₂H₅⁺ • 5) +  = (C₂H₅⁺ • 6)

By formula: (C₂H₅⁺ • 5CH₄) + CH₄ = (C₂H₅⁺ • 6CH₄)

(C₂H₅⁺ • 6) +  = (C₂H₅⁺ • 7)

By formula: (C₂H₅⁺ • 6CH₄) + CH₄ = (C₂H₅⁺ • 7CH₄)

(C₂H₅⁺ • 7) +  = (C₂H₅⁺ • 8)

By formula: (C₂H₅⁺ • 7CH₄) + CH₄ = (C₂H₅⁺ • 8CH₄)

(C₂H₅⁺ • 8) +  = (C₂H₅⁺ • 9)

By formula: (C₂H₅⁺ • 8CH₄) + CH₄ = (C₂H₅⁺ • 9CH₄)

(C₂H₅⁺ • 9) +  = (C₂H₅⁺ • 10)

By formula: (C₂H₅⁺ • 9CH₄) + CH₄ = (C₂H₅⁺ • 10CH₄)

C₂H₈F^- + 3 = C₃H₁₂F^-

By formula: C₂H₈F^- + 3CH₄ = C₃H₁₂F^-

C₃H₇⁺ +  = (C₃H₇⁺ • )

By formula: C₃H₇⁺ + CH₄ = (C₃H₇⁺ • CH₄)

(C₃H₇⁺ • ) +  = (C₃H₇⁺ • 2)

By formula: (C₃H₇⁺ • CH₄) + CH₄ = (C₃H₇⁺ • 2CH₄)

(C₃H₇⁺ • 2) +  = (C₃H₇⁺ • 3)

By formula: (C₃H₇⁺ • 2CH₄) + CH₄ = (C₃H₇⁺ • 3CH₄)

(C₃H₇⁺ • 3) +  = (C₃H₇⁺ • 4)

By formula: (C₃H₇⁺ • 3CH₄) + CH₄ = (C₃H₇⁺ • 4CH₄)

(C₃H₇⁺ • 4) +  = (C₃H₇⁺ • 5)

By formula: (C₃H₇⁺ • 4CH₄) + CH₄ = (C₃H₇⁺ • 5CH₄)

(C₃H₇⁺ • 5) +  = (C₃H₇⁺ • 6)

By formula: (C₃H₇⁺ • 5CH₄) + CH₄ = (C₃H₇⁺ • 6CH₄)

(C₃H₇⁺ • 6) +  = (C₃H₇⁺ • 7)

By formula: (C₃H₇⁺ • 6CH₄) + CH₄ = (C₃H₇⁺ • 7CH₄)

(C₃H₇⁺ • 7) +  = (C₃H₇⁺ • 8)

By formula: (C₃H₇⁺ • 7CH₄) + CH₄ = (C₃H₇⁺ • 8CH₄)

C₃H₁₂F^- + 4 = C₄H₁₆F^-

By formula: C₃H₁₂F^- + 4CH₄ = C₄H₁₆F^-

C₄H₉⁺ +  = (C₄H₉⁺ • )

By formula: C₄H₉⁺ + CH₄ = (C₄H₉⁺ • CH₄)

(C₄H₉⁺ • ) +  = (C₄H₉⁺ • 2)

By formula: (C₄H₉⁺ • CH₄) + CH₄ = (C₄H₉⁺ • 2CH₄)

(C₄H₉⁺ • 2) +  = (C₄H₉⁺ • 3)

By formula: (C₄H₉⁺ • 2CH₄) + CH₄ = (C₄H₉⁺ • 3CH₄)

(C₄H₉⁺ • 3) +  = (C₄H₉⁺ • 4)

By formula: (C₄H₉⁺ • 3CH₄) + CH₄ = (C₄H₉⁺ • 4CH₄)

(C₄H₉⁺ • 4) +  = (C₄H₉⁺ • 5)

By formula: (C₄H₉⁺ • 4CH₄) + CH₄ = (C₄H₉⁺ • 5CH₄)

(C₄H₉⁺ • 5) +  = (C₄H₉⁺ • 6)

By formula: (C₄H₉⁺ • 5CH₄) + CH₄ = (C₄H₉⁺ • 6CH₄)

(C₄H₉⁺ • 6) +  = (C₄H₉⁺ • 7)

By formula: (C₄H₉⁺ • 6CH₄) + CH₄ = (C₄H₉⁺ • 7CH₄)

(C₄H₉⁺ • 7) +  = (C₄H₉⁺ • 8)

By formula: (C₄H₉⁺ • 7CH₄) + CH₄ = (C₄H₉⁺ • 8CH₄)

(C₄H₉⁺ • 8) +  = (C₄H₉⁺ • 9)

By formula: (C₄H₉⁺ • 8CH₄) + CH₄ = (C₄H₉⁺ • 9CH₄)

C₄H₁₆F^- + 5 = C₅H₂₀F^-

By formula: C₄H₁₆F^- + 5CH₄ = C₅H₂₀F^-

C₅H₂₀F^- + 6 = C₆H₂₄F^-

By formula: C₅H₂₀F^- + 6CH₄ = C₆H₂₄F^-

C₅MnO₅⁺ +  = (C₅MnO₅⁺ • )

By formula: C₅MnO₅⁺ + CH₄ = (C₅MnO₅⁺ • CH₄)

C₆H₂₄F^- + 7 = C₇H₂₈F^-

By formula: C₆H₂₄F^- + 7CH₄ = C₇H₂₈F^-

C₇H₂₈F^- + 8 = C₈H₃₂F^-

By formula: C₇H₂₈F^- + 8CH₄ = C₈H₃₂F^-

C₈H₃₂F^- + 9 = C₉H₃₆F^-

By formula: C₈H₃₂F^- + 9CH₄ = C₉H₃₆F^-

C₉H₃₆F^- + 10 = C₁₀H₄₀F^-

By formula: C₉H₃₆F^- + 10CH₄ = C₁₀H₄₀F^-

 +  = CH₄Cl^-

By formula: Cl^- + CH₄ = CH₄Cl^-

 +  = ( • )

By formula: Co⁺ + CH₄ = (Co⁺ • CH₄)

Enthalpy of reaction

( • ) +  = ( • 2)

By formula: (Co⁺ • CH₄) + CH₄ = (Co⁺ • 2CH₄)

Enthalpy of reaction

( • 2) +  = ( • 3)

By formula: (Co⁺ • 2CH₄) + CH₄ = (Co⁺ • 3CH₄)

Enthalpy of reaction

Free energy of reaction

( • 3) +  = ( • 4)

By formula: (Co⁺ • 3CH₄) + CH₄ = (Co⁺ • 4CH₄)

Enthalpy of reaction

( • ) +  = ( •  • )

By formula: (Co⁺ • C₂H₆) + CH₄ = (Co⁺ • CH₄ • C₂H₆)

Enthalpy of reaction

( • ) +  = ( •  • )

By formula: (Co⁺ • H₂O) + CH₄ = (Co⁺ • CH₄ • H₂O)

Enthalpy of reaction

( • ) +  = ( •  • )

By formula: (Co⁺ • H₂) + CH₄ = (Co⁺ • CH₄ • H₂)

Enthalpy of reaction

 +  = CH₄F^-

By formula: F^- + CH₄ = CH₄F^-

 +  = ( • )

By formula: Fe⁺ + CH₄ = (Fe⁺ • CH₄)

Enthalpy of reaction

( • ) +  = ( • 2)

By formula: (Fe⁺ • CH₄) + CH₄ = (Fe⁺ • 2CH₄)

Enthalpy of reaction

( • 2) +  = ( • 3)

By formula: (Fe⁺ • 2CH₄) + CH₄ = (Fe⁺ • 3CH₄)

Enthalpy of reaction

( • 3) +  = ( • 4)

By formula: (Fe⁺ • 3CH₄) + CH₄ = (Fe⁺ • 4CH₄)

Enthalpy of reaction

 +  = ( • )

By formula: H₃O⁺ + CH₄ = (H₃O⁺ • CH₄)

( • ) +  = ( • 2)

By formula: (H₃O⁺ • CH₄) + CH₄ = (H₃O⁺ • 2CH₄)

H₃S⁺ +  = (H₃S⁺ • )

By formula: H₃S⁺ + CH₄ = (H₃S⁺ • CH₄)

 +  = ( • )

By formula: H₄N⁺ + CH₄ = (H₄N⁺ • CH₄)

 +  = CH₄I^-

By formula: I^- + CH₄ = CH₄I^-

 +  = ( • )

By formula: Mg⁺ + CH₄ = (Mg⁺ • CH₄)

( • ) +  = ( • 2)

By formula: (Mg⁺ • CH₄) + CH₄ = (Mg⁺ • 2CH₄)

 +  = ( • )

By formula: Na⁺ + CH₄ = (Na⁺ • CH₄)

IR Spectrum

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

Data compiled by: Coblentz Society, Inc.

• GAS (150 mmHg DILUTED TO A TOTAL PRESSURE OF 600 mmHg WITH N2); DOW KBr FOREPRISM; DIGITIZED BY NIST FROM HARD COPY (FROM TWO SEGMENTS); 4 cm^-1 resolution

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

• gas

Mass spectrum (electron ionization)

Go To: Top, Henry's Law data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Vibrational and/or electronic energy levels, 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

Vibrational and/or electronic energy levels

Go To: Top, Henry's Law data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, 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:   T_d     Symmetry Number σ = 12

Source: Shimanouchi, 1972

Notes

References

Go To: Top, Henry's Law data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, 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.

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]

Berkowitz, Greene, et al., 1987
Berkowitz, J.; Greene, J.P.; Cho, H.; Ruscic, B., The ionization potentials of CH₄ and CD₄, J. Chem. Phys., 1987, 86, 674. [all data]

Chatham, Hils, et al., 1984
Chatham, H.; Hils, D.; Robertson, R.; Gallagher, A., Total and partial electron collisional ionization cross sections for CH₄, C₂H₆, SiH₄, and Si₂H₆, J. Chem. Phys., 1984, 81, 1770. [all data]

Plessis, Marmet, et al., 1983
Plessis, P.; Marmet, P.; Dutil, R., Ionization and appearance potentials of CH₄ by electron impact, J. Phys. B:, 1983, 16, 1283. [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]

Bieri, Burger, et al., 1977
Bieri, G.; Burger, F.; Heilbronner, E.; Maier, J.P., Valence ionization enrgies of hydrocarbons, Helv. Chim. Acta, 1977, 60, 2213. [all data]

Selim and El-Kholy, 1975
Selim, E.T.M.; El-Kholy, S.B., Mass spectrometric ionization and dissociation of methane, Indian J. Pure Appl. Phys., 1975, 13, 233. [all data]

Debies and Rabalais, 1975
Debies, T.P.; Rabalais, J.W., Calculated photoionization cross-sections and angular distributions for the isoelectronic series Ne, HF, H₂O, NH₃, and CH₄, J. Am. Chem. Soc., 1975, 97, 487. [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]

Morrison and Traeger, 1973
Morrison, J.D.; Traeger, J.C., Ionization and dissociation by electron impact. III. CH₄ and SiH₄, Int. J. Mass Spectrom. Ion Phys., 1973, 11, 289. [all data]

Potts and Price, 1972
Potts, A.W.; Price, W.C., The photoelectron spectra of methane, silane germane and stannane, Proc. R. Soc. London A:, 1972, 165. [all data]

Finney and Harrison, 1972
Finney, C.D.; Harrison, A.G., A third-derivative method for determining electron-impact onset potentials, Int. J. Mass Spectrom. Ion Phys., 1972, 9, 221. [all data]

Bergmark, Rabalais, et al., 1972
Bergmark, T.; Rabalais, J.W.; Werme, L.O.; Karlsson, L.; Siegbahn, K., High-resolution electron spectra of methane, thiophene, 2-bromothiphene, and 3-bromothiophene in Electron Spectroscopy, ed. D.A. Shirley (North-Holland Pub. Co., Amsterdam), 1972. [all data]

Rabalais, Bergmark, et al., 1971
Rabalais, J.W.; Bergmark, T.; Werme, L.O.; Karlsson, L.; Siegbahn, K., The Jahn-Teller effect in the electron spectrum of methane, Phys. Scr., 1971, 3, 13. [all data]

Chupka and Berkowitz, 1971
Chupka, W.A.; Berkowitz, J., Photoionization of methane: ionization potential and proton affinity of CH₄, J. Chem. Phys., 1971, 54, 4256. [all data]

Pullen, Carlson, et al., 1970
Pullen, B.P.; Carlson, T.A.; Moddeman, W.E.; Schweitzer, G.K.; Bull, W.E., Photoelectron spectra of methane, silane, germane, methyl fluoride, difluoromethane, and trifluoromethane, J. Chem. Phys., 1970, 53, 768. [all data]

Brundle, Robin, et al., 1970
Brundle, C.R.; Robin, M.B.; Basch, H., Electronic energies and electronic structures of the fluoromethanes, J. Chem. Phys., 1970, 53, 2196. [all data]

Lossing and Semeluk, 1969
Lossing, F.P.; Semeluk, G.P., Threshold ionization efficiency curves for monoenergetic electron impact on H₂, D₂, CH₄ and CD₄, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 408. [all data]

Williams and Hamill, 1968
Williams, J.M.; Hamill, W.H., Ionization potentials of molecules and free radicals and appearance potentials by electron impact in the mass spectrometer, J. Chem. Phys., 1968, 49, 4467. [all data]

Villarejo, Stockbauer, et al., 1968
Villarejo, D.; Stockbauer, R.; Inghram, M.G., Measurement of threshold electrons in the photoionization of small molecules, Bull. Am. Phys. Soc., 1968, 13, 39. [all data]

Cermak, 1968
Cermak, V., Penning ionization electron spectroscopy. I. Determination of ionization potentials of polyatomic molecules, Collection Czech. Chem. Commun., 1968, 33, 2739. [all data]

Baker, Baker, et al., 1968
Baker, A.D.; Baker, C.; Brundle, C.R.; Turner, D.W., The electronic structures of methane, ethane, ethylene and formaldehyde studied by high-resolution molecular photoelectron spectroscopy, Intern. J. Mass Spectrom. Ion Phys., 1968, 1, 285. [all data]

Brehm, 1966
Brehm, B., Massenspektrometrische Untersuchung der Photoionisation von Molekulen, Z. Naturforsch., 1966, 21a, 196. [all data]

Nicholson, 1965
Nicholson, A.J.C., Photoionization-efficiency curves. II. False and genuine structure, J. Chem. Phys., 1965, 43, 1171. [all data]

Dibeler, Krauss, et al., 1965
Dibeler, V.H.; Krauss, M.; Reese, R.M.; Harllee, F.N., Mass-spectrometric study of photoionization. III. Methane and methane-d₄, J. Chem. Phys., 1965, 42, 3791. [all data]

Melton and Hamill, 1964
Melton, C.E.; Hamill, W.H., Appearance potentials by the retarding potential-difference method for secondary ions produced by excited-neutral, excited ion-neutral, and ion-neutral reactions, J. Chem. Phys., 1964, 41, 1469. [all data]

Bieri and Asbrink, 1980
Bieri, G.; Asbrink, L., 30.4-nm He(II) photoelectron spectra of organic molecules, J. Electron Spectrosc. Relat. Phenom., 1980, 20, 149. [all data]

Harshbarger, Robin, et al., 1973
Harshbarger, W.R.; Robin, M.B.; Lassettre, E.N., The electron impact spectra of the fluoromethanes, J. Electron Spectrosc. Relat. Phenom., 1973, 1, 319. [all data]

McCulloh and Dibeler, 1976
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Notes

Go To: Top, Henry's Law data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Mass spectrum (electron ionization), Vibrational and/or electronic energy levels, References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  T	Temperature
  d(ln(kH))/d(1/T)	Temperature dependence parameter for Henry's Law constant
  k°H	Henry's Law constant at 298.15K
  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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