Methoxy radical
- Formula: CH3O
- Molecular weight: 31.0339
- IUPAC Standard InChIKey: GRVDJDISBSALJP-UHFFFAOYSA-N
- CAS Registry Number: 2143-68-2
- Chemical structure:
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Gas phase thermochemistry data
Go To: Top, 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.
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔfH°gas | 4.1 ± 1. | kcal/mol | N/A | Tsang, 1996 |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, 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)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
IE (evaluated) | 10.72 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
ΔfH(+) ion,0K | 253.1 | kcal/mol | N/A | N/A |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
10.72 | DER | Ruscic and Berkowitz, 1991 | LL |
8.6 | DER | Lias, Bartmess, et al., 1988 | LL |
8.3 ± 0.3 | CIEL | Griffiths and Harris, 1987 | LBLHLM |
7.37 ± 0.03 | PE | Dyke, 1987 | LBLHLM |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
CHO+ | 8.73 | H2 | PI | Kuo, Zhang, et al., 1994 | LL |
Anion protonation reactions
CH3O- + =
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 382. ± 2. | kcal/mol | AVG | N/A | Average of 6 values; Individual data points |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 376.02 ± 0.62 | kcal/mol | H-TS | Nee, Osterwalder, et al., 2006 | gas phase; B |
ΔrG° | 376.04 ± 0.55 | kcal/mol | H-TS | Osborn, Leahy, et al., 1998 | gas phase; B |
ΔrG° | 374.0 ± 2.0 | kcal/mol | IMRE | Bartmess, Scott, et al., 1979 | gas phase; The acidity is 1.2 kcal/mol stronger than that from the D-EA cycle, due to the multi-compound fit for the acidity scale.; value altered from reference due to change in acidity scale; B |
ΔrG° | 374.6 ± 2.1 | kcal/mol | H-TS | Haas and Harrison, 1993 | gas phase; Both metastable and 50 eV collision energy.; B |
ΔrG° | 375.10 ± 0.60 | kcal/mol | TDEq | Meot-ner and Sieck, 1986 | gas phase; Experimental entropy: 21.5 eu, 0.6 less than H2O; B |
References
Go To: Top, Gas phase thermochemistry data, 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.
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]
Notes
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, 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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