Methoxy radical

• Formula: CH₃O
• Molecular weight: 31.0339
• IUPAC Standard InChI: InChI=1S/CH3O/c1-2/h1H3 Copy

  
• IUPAC Standard InChIKey: GRVDJDISBSALJP-UHFFFAOYSA-N Copy
• CAS Registry Number: 2143-68-2
• 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.
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• Information on this page:
  • Gas phase thermochemistry data
  • Gas phase ion energetics data
  • Vibrational and/or electronic energy levels
  • References
  • Notes
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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Gas phase thermochemistry data

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

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, 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 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
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard

View reactions leading to CH₃O⁺ (ion structure unspecified)

Ionization energy determinations

Appearance energy determinations

Anion protonation reactions

CH₃O^- +  =

By formula: CH₃O^- + H⁺ = CH₄O

Vibrational and/or electronic energy levels

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: Marilyn E. Jacox

State:   A

State:   X

Additional references: Jacox, 1994, page 236; Jacox, 1998, page 271; Jacox, 2003, page 257; Radford and Russell, 1977; Inoue, Akimoto, et al., 1979; Russell and Radford, 1980; Endo, Saito, et al., 1984; Fuke, Ozawa, et al., 1986; Agrawalla and Setser, 1986; Wantuck, Oldenborg, et al., 1987; Lin, Lee, et al., 1988; Momose, Endo, et al., 1988; Suto, Ye, et al., 1988; Geers, Kappert, et al., 1990; Powers, Pushkarsky, et al., 1997, 2; Applegate, Pushkarsky, et al., 1999; Liu, Chen, et al., 2009, 2

Notes

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, 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.

Tsang, 1996
Tsang, W., Heats of Formation of Organic Free Radicals by Kinetic Methods in Energetics of Organic Free Radicals, Martinho Simoes, J.A.; Greenberg, A.; Liebman, J.F., eds., Blackie Academic and Professional, London, 1996, 22-58. [all data]

Ruscic and Berkowitz, 1991
Ruscic, B.; Berkowitz, J., Photoionization mass spectrometric studies of the isomeric transient species CD₂OH and CD₃O, J. Chem. Phys., 1991, 95, 4033. [all data]

Lias, Bartmess, et al., 1988
Lias, S.G.; Bartmess, J.E.; Liebman, J.F.; Holmes, J.L.; Levin, R.D.; Mallard, W.G., Gas-phase ion and neutral thermochemistry, J. Phys. Chem. Ref. Data, Suppl. 1, 1988, 17, 1-861. [all data]

Griffiths and Harris, 1987
Griffiths, W.J.; Harris, F.M., Ionization energies of CH₃O and CH₃S radicals measured by charge-inversion energy-loss spectrometry, Chem. Phys. Lett., 1987, 142, 7. [all data]

Dyke, 1987
Dyke, J.M., Properties of gas-phase ions, J. Chem. Soc. Faraday Trans., 1987, 83, 69. [all data]

Kuo, Zhang, et al., 1994
Kuo, S.-C.; Zhang, Z.; Klemm, R.B.; Liebman, J.F.; Stief, L.J.; Nesbitt, F.L., Photoionization of hydroxymethyl (CD₂OH and CD₃O) radicals: Photoion efficiency spectra, ionization energies and thermochemistry, J. Phys. Chem., 1994, 98, 4026. [all data]

Nee, Osterwalder, et al., 2006
Nee, M.J.; Osterwalder, A.; Zhou, J.; Neumark, D.M., Slow electron velocity-map imaging photoelectron spectra of the methoxide anion, J. Chem. Phys., 2006, 125, 1, 014306, https://doi.org/10.1063/1.2212411 . [all data]

Osborn, Leahy, et al., 1998
Osborn, D.L.; Leahy, D.J.; Kim, E.H.; deBeer, E.; Neumark, D.M., Photoelectron spectroscopy of CH3O- and CD3O-, Chem. Phys. Lett., 1998, 292, 4-6, 651-655, https://doi.org/10.1016/S0009-2614(98)00717-9 . [all data]

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Haas and Harrison, 1993
Haas, M.J.; Harrison, A.G., The Fragmentation of Proton-Bound Cluster Ions and the Gas-Phase Acidities of Alcohols, Int. J. Mass Spectrom. Ion Proc., 1993, 124, 2, 115, https://doi.org/10.1016/0168-1176(93)80003-W . [all data]

Meot-ner and Sieck, 1986
Meot-ner, M.; Sieck, L.W., Relative acidities of water and methanol, and the stabilities of the dimer adducts, J. Phys. Chem., 1986, 90, 6687. [all data]

Style and Ward, 1953
Style, D.W.G.; Ward, J.C., Fluorescent spectra from ethyl nitrate. Part 1.?Supposed emissions from alkoxy radicals and NO2, Trans. Faraday Soc., 1953, 49, 999, https://doi.org/10.1039/tf9534900999 . [all data]

Ohbayashi, Akimoto, et al., 1977
Ohbayashi, K.; Akimoto, H.; Tanaka, I., Emission spectra of methoxyl, ethoxyl, and isopropoxyl radicals, J. Phys. Chem., 1977, 81, 8, 798, https://doi.org/10.1021/j100523a023 . [all data]

Wendt and Hunziker, 1979
Wendt, H.R.; Hunziker, H.E., Electronic absorption spectrum of CH3O, J. Chem. Phys., 1979, 71, 12, 5202, https://doi.org/10.1063/1.438296 . [all data]

Inoue, Akimoto, et al., 1980
Inoue, G.; Akimoto, H.; Okuda, M., Spectroscopy of the CH3O A 2A1--X 2E system by laser-excited fluorescence method, J. Chem. Phys., 1980, 72, 3, 1769, https://doi.org/10.1063/1.439291 . [all data]

Powers, Hopkins, et al., 1981
Powers, E.; Hopkins, J.B.; Smalley, R.E., Laser production of jet-cooled radicals. Methoxy and methoxy-argon, J. Phys. Chem., 1981, 85, 19, 2711, https://doi.org/10.1021/j150619a003 . [all data]

Carrick, Brossard, et al., 1985
Carrick, P.G.; Brossard, S.D.; Engelking, P.C., Experimental observation of the spin-orbit splitting in methoxy, J. Chem. Phys., 1985, 83, 4, 1995, https://doi.org/10.1063/1.449338 . [all data]

Brossard, Carrick, et al., 1986
Brossard, S.D.; Carrick, P.G.; Chappell, E.L.; Hulegaard, S.C.; Engelking, P.C., The 2A1--2E electronic spectrum of methoxy, CH3O: Vibrational progressions, and spin-orbit and Jahn--Teller couplings, J. Chem. Phys., 1986, 84, 5, 2459, https://doi.org/10.1063/1.450364 . [all data]

Garland, 1988
Garland, N.L., and D. R. Crosley, 1988, J. Phys. Chem. 92, 5322. [all data]

Foster, Misra, et al., 1988
Foster, S.C.; Misra, P.; Lin, T.-Y.; Damo, C.P.; Carter, C.C.; Miller, T.A., Free jet-cooled laser-induced fluorescence spectrum of methoxy. 1. Vibronic analysis of the ~A and ~X states, J. Phys. Chem., 1988, 92, 21, 5914, https://doi.org/10.1021/j100332a014 . [all data]

Liu, Damo, et al., 1989
Liu, X.; Damo, C.P.; Lin, T.-Y.D.; Foster, S.C.; Misra, P.; Yu, L.; Miller, T.A., Free jet-cooled laser-induced fluorescence spectrum of methoxy radical. 2. Rotational analysis of the ~A2A1 .tautm. ~X2E electronic transition, J. Phys. Chem., 1989, 93, 6, 2266, https://doi.org/10.1021/j100343a016 . [all data]

Kappert and Temps, 1989
Kappert, J.; Temps, F., Rotationally resolved laser-induced fluorescence excitation studies of CH3O, Chem. Phys., 1989, 132, 1-2, 197, https://doi.org/10.1016/0301-0104(89)80088-6 . [all data]

Liu, Foster, et al., 1990
Liu, X.; Foster, S.C.; Williamson, J.M.; Yu, L.; Miller, T.A., The spin-rotation interactions in the methoxy radical, Mol. Phys., 1990, 69, 2, 357, https://doi.org/10.1080/00268979000100251 . [all data]

Lee, Wann, et al., 1993
Lee, Y.-Y.; Wann, G.-H.; Lee, Y.-P., Vibronic analysis of the A→X laser-induced fluorescence of jet-cooled methoxy (CH3O) radical, J. Chem. Phys., 1993, 99, 12, 9465, https://doi.org/10.1063/1.465481 . [all data]

Geers, Kappert, et al., 1994
Geers, A.; Kappert, J.; Temps, F.; Wiebrecht, J.W., Rotation--vibration state resolved unimolecular dynamics of highly vibrationally excited CH3O (X 2E). I. Observed stimulated emission pumping spectra, J. Chem. Phys., 1994, 101, 5, 3618, https://doi.org/10.1063/1.467547 . [all data]

Osborn, Leahy, et al., 1995
Osborn, D.L.; Leahy, D.J.; Ross, E.M.; Neumark, D.M., Study of the predissociation of by fast beam photofragment translational spectroscopy, Chem. Phys. Lett., 1995, 235, 5-6, 484, https://doi.org/10.1016/0009-2614(95)00151-S . [all data]

Powers, Pushkarsky, et al., 1997
Powers, D.E.; Pushkarsky, M.B.; Miller, T.A., Rovibronic analysis of the laser induced fluorescence excitation spectrum of the jet-cooled methoxy radical, J. Chem. Phys., 1997, 106, 17, 6863, https://doi.org/10.1063/1.473712 . [all data]

Liu, Chen, et al., 2009
Liu, J.; Chen, M.-W.; Melnik, D.; Yi, J.T.; Miller, T.A., The spectroscopic characterization of the methoxy radical. I. Rotationally resolved A [sup 2]A[sub 1]--X [sup 2]E electronic spectra of CH[sub 3]O, J. Chem. Phys., 2009, 130, 7, 074302, https://doi.org/10.1063/1.3072104 . [all data]

Chiang, Hsu, et al., 1989
Chiang, S.-Y.; Hsu, Y.-C.; Lee, Y.-P., Laser-induced emission of CH3O in solid argon, J. Chem. Phys., 1989, 90, 1, 81, https://doi.org/10.1063/1.456471 . [all data]

Temps, 1995
Temps, F., VIBRATIONAL SPECTROSCOPY, INTRAMOLECULAR DYNAMICS AND STATE SPECIFIC UNIMOLECULAR DISSOCIATION OF, Adv. Ser. Phys. Chem., 1995, 4, 375. [all data]

Ebata, Yanagishita, et al., 1982
Ebata, T.; Yanagishita, H.; Obi, K.; Tanaka, I., Ã→X fluorescence spectra of CH3O and C2H5O generated by the Arf laser photolysis of alkyl nitrites, Chem. Phys., 1982, 69, 1-2, 27, https://doi.org/10.1016/0301-0104(82)88129-9 . [all data]

Han, Utkin, et al., 2002
Han, J.-X.; Utkin, Yu.G.; Chen, H.-B.; Burns, L.A.; Curl, R.F., High-resolution infrared spectra of the C-H asymmetric stretch vibration of jet-cooled methoxy radical (CH[sub 3]O), J. Chem. Phys., 2002, 117, 14, 6538, https://doi.org/10.1063/1.1507116 . [all data]

Han, Hu, et al., 2007
Han, J.; Hu, S.; Chen, H.; Utkin, Y.; Brown, J.M.; Curl, R.F., Jet-cooled infrared spectrum of methoxy in the CH stretching region, Phys. Chem. Chem. Phys., 2007, 9, 28, 3725, https://doi.org/10.1039/b700502d . [all data]

Osborn, Leahy, et al., 1998, 2
Osborn, D.L.; Leahy, D.J.; Kim, E.H.; de Beer, E.; Neumark, D.M., Photoelectron spectroscopy of CH3O- and CD3O-, Chem. Phys. Lett., 1998, 292, 4-6, 651, https://doi.org/10.1016/S0009-2614(98)00717-9 . [all data]

Ramond, Davico, et al., 2000
Ramond, T.M.; Davico, G.E.; Schwartz, R.L.; Lineberger, W.C., Vibronic structure of alkoxy radicals via photoelectron spectroscopy, J. Chem. Phys., 2000, 112, 3, 1158, https://doi.org/10.1063/1.480767 . [all data]

Geers, Kappert, et al., 1993
Geers, A.; Kappert, J.; Temps, F.; Sears, T.J., Stimulated emission pumping spectroscopy of CH3O (X 2E, ν6): New observations on the Jahn--Teller effect, J. Chem. Phys., 1993, 98, 5, 4297, https://doi.org/10.1063/1.465036 . [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]

Jacox, 1998
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement A, J. Phys. Chem. Ref. Data, 1998, 27, 2, 115-393, https://doi.org/10.1063/1.556017 . [all data]

Jacox, 2003
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement B, J. Phys. Chem. Ref. Data, 2003, 32, 1, 1-441, https://doi.org/10.1063/1.1497629 . [all data]

Radford and Russell, 1977
Radford, H.E.; Russell, D.K., Spectroscopic detection of methoxy (CH3O), J. Chem. Phys., 1977, 66, 5, 2222, https://doi.org/10.1063/1.434142 . [all data]

Inoue, Akimoto, et al., 1979
Inoue, G.; Akimoto, H.; Okuda, M., Laser-induced fluorescence spectra of CH3O, Chem. Phys. Lett., 1979, 63, 2, 213, https://doi.org/10.1016/0009-2614(79)87002-5 . [all data]

Russell and Radford, 1980
Russell, D.K.; Radford, H.E., Analysis of the LMR spectra of methoxy, CH3O, J. Chem. Phys., 1980, 72, 4, 2750, https://doi.org/10.1063/1.439423 . [all data]

Endo, Saito, et al., 1984
Endo, Y.; Saito, S.; Hirota, E., The microwave spectrum of the methoxy radical CH3O, J. Chem. Phys., 1984, 81, 1, 122, https://doi.org/10.1063/1.447375 . [all data]

Fuke, Ozawa, et al., 1986
Fuke, K.; Ozawa, K.; Kaya, K., Electronic spectra and predissociation of jet-cooled CH3O and CH3O-Ar in the Ã2A1 state, Chem. Phys. Lett., 1986, 126, 2, 119, https://doi.org/10.1016/S0009-2614(86)80023-9 . [all data]

Agrawalla and Setser, 1986
Agrawalla, B.S.; Setser, D.W., Infrared chemiluminescence and laser-induced fluorescence studies of energy disposal by reactions of fluorine and chlorine atoms with hydrogen sulfide, deuterium sulfide, hydrogen selenide, water, water-d2, and methanol, J. Phys. Chem., 1986, 90, 11, 2450, https://doi.org/10.1021/j100402a039 . [all data]

Wantuck, Oldenborg, et al., 1987
Wantuck, P.J.; Oldenborg, R.C.; Baughcum, S.L.; Winn, K.R., Collisional quenching of methoxy(A2A1) radical, J. Phys. Chem., 1987, 91, 12, 3253, https://doi.org/10.1021/j100296a030 . [all data]

Lin, Lee, et al., 1988
Lin, S.-R.; Lee, Y.-P.; Nee, J.B., Radiative lifetime and quenching of the A 2A1 state of the CH3O radical, J. Chem. Phys., 1988, 88, 1, 171, https://doi.org/10.1063/1.454633 . [all data]

Momose, Endo, et al., 1988
Momose, T.; Endo, Y.; Hirota, E.; Shida, T., The submillimeter-wave spectrum of the 13CH3O radical, J. Chem. Phys., 1988, 88, 9, 5338, https://doi.org/10.1063/1.454593 . [all data]

Suto, Ye, et al., 1988
Suto, M.; Ye, C.; Lee, L.C., CH3O(A--X) fluorescence from photodissociation of dimethyl ether, J. Chem. Phys., 1988, 89, 10, 6555, https://doi.org/10.1063/1.455378 . [all data]

Geers, Kappert, et al., 1990
Geers, A.; Kappert, J.; Temps, F.; Wiebrecht, J.W., Stimulated-emission pumping spectroscopy of highly excited states of CH_3O (X~ ^2E): zero-order vibrational states at 3000 cm^-1 ≤ 9000 cm^-1, J. Opt. Soc. Am. B, 1990, 7, 9, 1935, https://doi.org/10.1364/JOSAB.7.001935 . [all data]

Powers, Pushkarsky, et al., 1997, 2
Powers, D.E.; Pushkarsky, M.B.; Miller, T.A., Vibrational mode and frequency dependence of the photofragmentation of the methoxy radical, J. Chem. Phys., 1997, 106, 17, 6878, https://doi.org/10.1063/1.473713 . [all data]

Applegate, Pushkarsky, et al., 1999
Applegate, B.E.; Pushkarsky, M.B.; Miller, T.A., Spectral Analysis and Photofragmentation Dynamics of the Perdeuteromethoxy Radical, J. Phys. Chem. A, 1999, 103, 11, 1538, https://doi.org/10.1021/jp984141n . [all data]

Liu, Chen, et al., 2009, 2
Liu, J.; Chen, M.-W.; Melnik, D.; Miller, T.A.; Endo, Y.; Hirota, E., The spectroscopic characterization of the methoxy radical. II. Rotationally resolved A [sup 2]A[sub 1]-X [sup 2]E electronic and X [sup 2]E microwave spectra of the perdeuteromethoxy radical CD[sub 3]O, J. Chem. Phys., 2009, 130, 7, 074303, https://doi.org/10.1063/1.3072105 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  ΔfH(+) ion,0K	Enthalpy of formation of positive ion at 0K
  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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