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Methyl radical

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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:
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
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

View reactions leading to CH3+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)9.84 ± 0.01eVN/AN/AL
Quantity Value Units Method Reference Comment
Deltaf(+) ion1095.kJ/molN/AN/A 
Quantity Value Units Method Reference Comment
DeltafH(+) ion,0K1099.kJ/molN/AN/A 

Electron affinity determinations

EA (eV) Method Reference Comment
0.080 ± 0.030LPESEllison, Engelking, et al., 1978B
<0.499990PDFeldman, Rackwitz, et al., 1977B
<0.6244 ± 0.0053D-EABohme, Lee-Ruff, et al., 1972B
0.12983N/ACheck, Faust, et al., 2001FeBr3; ; «DELTA»S(EA)=9.3; B
1.12747SIPage, 1972The Magnetron method, lacking mass analysis, is not considered reliable.; B
1.0 ± 1.1SIPage and Goode, 1969The Magnetron method, lacking mass analysis, is not considered reliable.; B
1.07543SIGaines and Page, 1968The Magnetron method, lacking mass analysis, is not considered reliable.; B

Ionization energy determinations

IE (eV) Method Reference Comment
9.843 ± 0.002EVALBerkowitz, Ellison, et al., 1994LL
9.84DERNagano, Murthy, et al., 1993LL
9.84 ± 0.02PEHoule and Beauchamp, 1979LLK
9.84 ± 0.05EIReeher, Flesch, et al., 1976LLK
9.6 ± 0.3EIKaposi, Riedel, et al., 1975LLK
9.837 ± 0.005PEGolob, Jonathan, et al., 1973LLK
9.86 ± 0.04PEPotts, Glenn, et al., 1972LLK
9.81 ± 0.02PEJonathan, 1972LLK
9.84 ± 0.03EILossing and Semeluk, 1970RDSH
9.87 ± 0.05EIWilliams and Hamill, 1968RDSH
9.83 ± 0.01PIChupka and Lifshitz, 1968RDSH
9.82 ± 0.04PIElder, Giese, et al., 1962RDSH
9.842 ± 0.002SHerzberg and Shoosmith, 1956RDSH
9.840 ± 0.005PEDyke, Jonathan, et al., 1976Vertical value; LLK
9.82 ± 0.02PEKoenig, Balle, et al., 1975Vertical value; LLK
9.86 ± 0.04PEPotts, Glenn, et al., 1972, 2Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CH+15.58 ± 0.30H2EIWaldron, 1956RDSH
CH2+15.09 ± 0.03HPIChupka and Lifshitz, 1968RDSH

Cation De-protonation reactions

CH2- + Hydrogen cation = Methyl cation

By formula: CH2- + H+ = CH3+

Quantity Value Units Method Reference Comment
Deltar1711.7 ± 1.7kJ/molD-EALeopold, Murray, et al., 1985gas phase; Singlet-triplet splitting of CH2 = 9.0 kcal; B
Quantity Value Units Method Reference Comment
Deltar1679.5 ± 2.0kJ/molH-TSLeopold, Murray, et al., 1985gas phase; Singlet-triplet splitting of CH2 = 9.0 kcal; B

References

Go To: Top, Gas phase ion energetics data, Notes

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

Ellison, Engelking, et al., 1978
Ellison, G.B.; Engelking, P.C.; Lineberger, W.C., An experimental determination of the geometry and electron affinity of CH3, J. Am. Chem. Soc., 1978, 100, 2556. [all data]

Feldman, Rackwitz, et al., 1977
Feldman, D.; Rackwitz, R.; Kaiser, H.J.; Heincke, E., Photodetachment bei einigen neagtiven molekulionen: P2-, As2-, CH2-, CH3-, S3-, Z. Naturforsch. A:, 1977, 32, 600. [all data]

Bohme, Lee-Ruff, et al., 1972
Bohme, D.K.; Lee-Ruff, E.; Young, L.B., Acidity order of selected bronsted acids in the gas phase at 300K, J. Am. Chem. Soc., 1972, 94, 5153. [all data]

Check, Faust, et al., 2001
Check, C.E.; Faust, T.O.; Bailey, J.M.; Wright, B.J.; Gilbert, T.M.; Sunderlin, L.S., Addition of Polarization and Diffuse Functions to the LANL2DZ Basis Set for P-Block Elements, J. Phys. Chem. A,, 2001, 105, 34, 8111, https://doi.org/10.1021/jp011945l . [all data]

Page, 1972
Page, F.M., Experimental determination of the electron affinities of inorganic radicals, Adv. Chem. Ser., 1972, 36, 68. [all data]

Page and Goode, 1969
Page, F.M.; Goode, G.C., Negative Ions and the Magnetron., Wiley, NY, 1969. [all data]

Gaines and Page, 1968
Gaines, A.F.; Page, F.M., The Stabilities of Negative Ions.I. The Methyl-, Diphenylmethyl, and Triphenylmethyl Negative Ions, Int. J. Mass Spectrom. Ion Phys., 1968, 1, 4-5, 315, https://doi.org/10.1016/0020-7381(68)85008-9 . [all data]

Berkowitz, Ellison, et al., 1994
Berkowitz, J.; Ellison, G.B.; Gutman, D., Three methods to measure RH bond energies, J. Phys. Chem., 1994, 98, 2744. [all data]

Nagano, Murthy, et al., 1993
Nagano, Y.; Murthy, S.; Beauchamp, J.L., Thermochemical properties and gas-phase ion chemistry of phenylsilane investigated by FT-ICR spectrometry. Identification of parent- and fragment-ion structural isomers by their specific reactivities, J. Am. Chem. Soc., 1993, 115, 10805. [all data]

Houle and Beauchamp, 1979
Houle, F.A.; Beauchamp, J.L., Photoelectron spectroscopy of methyl, ethyl, isopropyl, and tert-butyl radicals. Implications for the thermochemistry and structures of the radicals and their corresponding carbonium ions, J. Am. Chem. Soc., 1979, 101, 4067. [all data]

Reeher, Flesch, et al., 1976
Reeher, J.R.; Flesch, G.D.; Svec, H.J., The mass spectra and ionization potentials of the neutral fragments produced during the electron bombardment of aromatic compounds, Org. Mass Spectrom., 1976, 11, 154. [all data]

Kaposi, Riedel, et al., 1975
Kaposi, O.; Riedel, M.; Sanchez, G.R., Mass-spectrometric study of electron-impact and heterogeneous pyrolytic decomposition of methyl bromide, Acta Chim. Acad. Sci. Hung., 1975, 85, 361. [all data]

Golob, Jonathan, et al., 1973
Golob, L.; Jonathan, N.; Morris, A.; Okuda, M.; Ross, K.J., The first ionization potential of the methyl radical as determined by photoelectron spectroscopy, J. Electron Spectrosc. Relat. Phenom., 1973, 1, 506. [all data]

Potts, Glenn, et al., 1972
Potts, A.W.; Glenn, K.G.; Price, W.C., General discussion, Faraday Discuss. Chem. Soc., 1972, 54, 64. [all data]

Jonathan, 1972
Jonathan, N., General discussion, Faraday Discuss. Chem. Soc., 1972, 54, 64. [all data]

Lossing and Semeluk, 1970
Lossing, F.P.; Semeluk, G.P., Free radicals by mass spectrometry. XLII.Ionization potentials and ionic heats of formation for C1-C4 alkyl radicals, Can. J. Chem., 1970, 48, 955. [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]

Chupka and Lifshitz, 1968
Chupka, W.A.; Lifshitz, C., Photoionization of CH3+; heat of formation of CH2, J. Chem. Phys., 1968, 48, 1109. [all data]

Elder, Giese, et al., 1962
Elder, F.A.; Giese, C.; Steiner, B.; Inghram, M., Photo-ionization of alkyl free radicals, J. Chem. Phys., 1962, 36, 3292. [all data]

Herzberg and Shoosmith, 1956
Herzberg, G.; Shoosmith, J., Absorption spectrum of free CH3 and CD3 radicals, Can. J. Phys., 1956, 34, 523. [all data]

Dyke, Jonathan, et al., 1976
Dyke, J.; Jonathan, N.; Lee, E.; Morris, A., Vacuum ultraviolet photoelectron spectroscopy of transient species, J. Chem. Soc. Faraday Trans. 2, 1976, 72, 1385. [all data]

Koenig, Balle, et al., 1975
Koenig, T.; Balle, T.; Snell, W., Helium(I) photoelectron spectra of organic radicals, J. Am. Chem. Soc., 1975, 97, 662. [all data]

Potts, Glenn, et al., 1972, 2
Potts, A.W.; Glenn, K.G.; Price, W.C., General discussion, Faraday Discuss. Chem. Soc., 1972, 54, 65. [all data]

Waldron, 1956
Waldron, J.D., The ionization and dissociation of methyl radicals on electron impact, Metropolitan Vickers Gaz., 1956, 27, 66. [all data]

Leopold, Murray, et al., 1985
Leopold, D.G.; Murray, K.K.; Miller, A.E.S.; Lineberger, W.C., Methylene: A study of the X3B1 and the 1A1 states by photoelectron spectroscopy of CH2- and CD2-, J. Chem. Phys., 1985, 83, 4849. [all data]


Notes

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