Methane, bromo-

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.


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.

Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Δfgas-8.2 ± 0.2kcal/molEqkFerguson, Okafo, et al., 1973 
Δfgas-9.0 ± 0.32kcal/molChydAdams, Carson, et al., 1966 
Δfgas-8.97 ± 0.35kcal/molChydFowell, Lacher, et al., 1965 

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry 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.

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 CH3Br+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)10.541 ± 0.003eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)158.7kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity152.5kcal/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
10.54SBaig, Connerade, et al., 1982LBLHLM
10.53PEKimura, Katsumata, et al., 1981LLK
10.53EIHolmes, Fingas, et al., 1981LLK
10.5 ± 0.2EIKaposi, Riedel, et al., 1976LLK
10.54 ± 0.01PITsai, Baer, et al., 1975LLK
10.5 ± 0.2EIKaposi, Riedel, et al., 1975LLK
10.541SHochmann, Templet, et al., 1975LLK
10.53PERagle, Stenhouse, et al., 1970RDSH
10.54PEPotts, Lempka, et al., 1970RDSH
10.53 ± 0.015PEHashmall and Heilbronner, 1970RDSH
10.53PIKrauss, Walker, et al., 1968RDSH
10.528 ± 0.005PINicholson, 1965RDSH
10.53 ± 0.01PIWatanabe, 1957RDSH
10.53 ± 0.02EIFrost and McDowell, 1957RDSH
10.541 ± 0.003SPrice, 1936RDSH
10.54PEAndrews, Dyke, et al., 1984Vertical value; LBLHLM
10.53PEUtsunomiya, Kobayashi, et al., 1980Vertical value; LLK
10.53PEUehara, Saito, et al., 1973Vertical value; LLK
10.70PEDixon, Murrell, et al., 1971Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
Br+15.8 ± 0.5CH3EIKaposi, Riedel, et al., 1976LLK
Br+15.8 ± 0.5CH3EIKaposi, Riedel, et al., 1975LLK
Br+14.7 ± 0.05CH3EITsuda, Melton, et al., 1964RDSH
HBr+15.9 ± 0.3CH2EIKaposi, Riedel, et al., 1976LLK
HBr+15.9 ± 0.3CH2EIKaposi, Riedel, et al., 1975LLK
C+22.9 ± 0.5H+H2+BrEIKaposi, Riedel, et al., 1976LLK
C+22.9 ± 0.5H+H2+BrEIKaposi, Riedel, et al., 1975LLK
CBr+18.8 ± 0.3H+H2EIKaposi, Riedel, et al., 1976LLK
CBr+18.8 ± 0.3H+H2EIKaposi, Riedel, et al., 1975LLK
CH+21.7 ± 0.3H2+BrEIKaposi, Riedel, et al., 1976LLK
CH+21.7 ± 0.3H2+BrEIKaposi, Riedel, et al., 1975LLK
CH+21.41?EIReed and Snedden, 1956RDSH
CHBr+16.3 ± 0.5H2EIKaposi, Riedel, et al., 1976LLK
CHBr+16.3 ± 0.5H2EIKaposi, Riedel, et al., 1975LLK
CH2+14.7 ± 0.5HBrEIKaposi, Riedel, et al., 1976LLK
CH2+14.7 ± 0.5HBrEIKaposi, Riedel, et al., 1975LLK
CH2+14.9 ± 0.2HBrEITsuda and Hamill, 1964RDSH
CH2Br+13.4 ± 0.3HEIKaposi, Riedel, et al., 1976LLK
CH2Br+13.4 ± 0.3HEIKaposi, Riedel, et al., 1975LLK
CH2Br+12.12 ± 0.09HEIMartin, Lampe, et al., 1966RDSH
CH3+12.77BrPITraeger and McLoughlin, 1981LLK
CH3+12.8 ± 0.3BrEIKaposi, Riedel, et al., 1976LLK
CH3+12.80 ± 0.03BrPITsai, Baer, et al., 1975LLK
CH3+12.8 ± 0.3BrEIKaposi, Riedel, et al., 1975LLK
CH3+9.60 ± 0.05Br-EIWilliams and Hamill, 1968RDSH
CH3+12.77BrPIKrauss, Walker, et al., 1968RDSH

De-protonation reactions

CH2Br- + Hydrogen cation = Methane, bromo-

By formula: CH2Br- + H+ = CH3Br

Quantity Value Units Method Reference Comment
Δr396.7 ± 2.5kcal/molEndoHierl, Henchman, et al., 1992gas phase; HO- + MeBr:6.0±2.3 kcal/mol endo. "Better than Ingemann and Nibbering, 19852" 2.0 kcal would not show barrier; B
Δr394.3 ± 4.6kcal/molEIAERogers, Simpson, et al., 2010gas phase; B
Δr392.7 ± 3.1kcal/molG+TSIngemann and Nibbering, 1985, 2gas phase; B
Quantity Value Units Method Reference Comment
Δr389.7 ± 3.4kcal/molH-TSHierl, Henchman, et al., 1992gas phase; HO- + MeBr:6.0±2.3 kcal/mol endo. "Better than Ingemann and Nibbering, 19852" 2.0 kcal would not show barrier; B
Δr385.8 ± 3.0kcal/molIMRBIngemann and Nibbering, 1985, 2gas phase; B

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

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

Mass spectrum
For Zoom
1.) Enter the desired X axis range (e.g., 100, 200)
2.) Check here for automatic Y scaling
3.) Press here to zoom

Additional Data

View image of digitized spectrum (can be printed in landscape orientation).

Due to licensing restrictions, this spectrum cannot be downloaded.

Owner NIST Mass Spectrometry Data Center
Collection (C) 2014 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
NIST MS number 19630

All mass spectra in this site (plus many more) are available from the NIST/EPA/NIH Mass Spectral Library. Please see the following for information about the library and its accompanying search program.


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.

Ferguson, Okafo, et al., 1973
Ferguson, K.C.; Okafo, E.N.; Whittle, E., Bond dissociation energies from equilibrium studies Part 4.-The equilibrium Br2 + CH4 = HBr + CH3Br. Determination of D(CH3-Br) and ΔHf°(CH3Br,g), J. Chem. Soc. Faraday Trans. 1, 1973, 69, 295-301. [all data]

Adams, Carson, et al., 1966
Adams, G.P.; Carson, A.S.; Laye, P.G., Thermochemistry of reductions caused by lithium aluminium hydride. Part 4.-Heat of formation of methyl bromide, Trans. Faraday Soc., 1966, 62, 1447-1449. [all data]

Fowell, Lacher, et al., 1965
Fowell, P.; Lacher, J.R.; Park, J.D., Reaction heats of organic compounds. Part 3.-Heats of hydrogenation of methyl bromide and ethyl bromide, Trans. Faraday Soc., 1965, 61, 1324-1327. [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]

Baig, Connerade, et al., 1982
Baig, M.A.; Connerade, J.P.; Hormes, J., Autoionisation resonances in the 4p(Π) spectrum of methyl bromide, J. Phys. B:, 1982, 15, 5. [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]

Holmes, Fingas, et al., 1981
Holmes, J.L.; Fingas, M.; Lossing, F.P., Towards a general scheme for estimating the heats of formation of organic ions in the gas phase. Part I. Odd-electron cations, Can. J. Chem., 1981, 59, 80. [all data]

Kaposi, Riedel, et al., 1976
Kaposi, O.; Riedel, M.; Vass-Balthazar, K.; Sanchez, G.R.; Lelik, L., Mass-spectrometric determination of thermochemical data of CHBr3 and CBr4 by study of their electron impact and heterogeneous pyrolytic decompositions, Acta Chim. Acad. Sci. Hung., 1976, 89, 221. [all data]

Tsai, Baer, et al., 1975
Tsai, B.P.; Baer, T.; Werner, A.S.; Lin, S.F., A photoelectron-photoion coincidence study of the ionization and fragment appearance potentials of bromo- and iodomethanes, J. Phys. Chem., 1975, 79, 570. [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]

Hochmann, Templet, et al., 1975
Hochmann, P.; Templet, P.H.; Wang, H.-t.; McGlynn, S.P., Molecular Rydberg transitions. I. Low-energy Rydberg transitions in methyl halides, J. Chem. Phys., 1975, 62, 2588. [all data]

Ragle, Stenhouse, et al., 1970
Ragle, J.L.; Stenhouse, I.A.; Frost, D.C.; McDowell, C.A., Valence-shell ionization potentials of halomethanes by photoelectron spectroscopy. I. CH3Cl, CH3Br, CH3I. Vibrational frequencies and vibronic interaction in CH3Br+ and CH3Cl+, J. Chem. Phys., 1970, 53, 178. [all data]

Potts, Lempka, et al., 1970
Potts, A.W.; Lempka, H.J.; Streets, D.G.; Price, W.C., Photoelectron spectra of the halides of elements in groups III, IV, V and VI, Phil. Trans. Roy. Soc. (London), 1970, A268, 59. [all data]

Hashmall and Heilbronner, 1970
Hashmall, J.A.; Heilbronner, E., n-Ionization potentials of alkyl bromides, Angew. Chem. Intern. Ed., 1970, 9, 305. [all data]

Krauss, Walker, et al., 1968
Krauss, M.; Walker, J.A.; Dibeler, V.H., Mass spectrometric study of photoionization. X. Hydrogen chloride and methyl halides, J. Res. NBS, 1968, 72A, 281. [all data]

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

Watanabe, 1957
Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

Frost and McDowell, 1957
Frost, D.C.; McDowell, C.A., Studies of the ionization of molecules by electron impact. II. Excited states of the molecular ions of methane and the methyl halides, Proc. Roy. Soc. (London), 1957, A241, 194. [all data]

Price, 1936
Price, W.C., The far ultraviolet absorption spectra and ionization potentials of the alkyl halides. Part I, J. Chem. Phys., 1936, 4, 539. [all data]

Andrews, Dyke, et al., 1984
Andrews, L.; Dyke, J.M.; Jonathan, N.; Keddar, N.; orris, A., The first bands in the photoelectron spectra of the CH2Br, CD2Br, CHBr2, and CH2I free radicals, J. Phys. Chem., 1984, 88, 1950. [all data]

Utsunomiya, Kobayashi, et al., 1980
Utsunomiya, C.; Kobayashi, T.; Nagakura, S., Photoelectron angular distribution measurements for some aliphatic alcohols, amines, halides, Bull. Chem. Soc. Jpn., 1980, 53, 1216. [all data]

Uehara, Saito, et al., 1973
Uehara, Y.; Saito, N.; Yonezawa, T., Ionization potentials of trifluoromethyl and methyl halides by photoelectron spectroscopy and calculations by extended Hucket and CNDO/2 methods, Chem. Lett., 1973, 495. [all data]

Dixon, Murrell, et al., 1971
Dixon, R.N.; Murrell, J.N.; Narayan, B., The photoelectron spectra of the halomethanes, Mol. Phys., 1971, 20, 611. [all data]

Tsuda, Melton, et al., 1964
Tsuda, S.; Melton, C.E.; Hamill, W.H., Ionization- efficiency curves for molecular and fragment ions from methane and the methyl halides, J. Chem. Phys., 1964, 41, 689. [all data]

Reed and Snedden, 1956
Reed, R.I.; Snedden, W., Studies in electron impact methods. Part 6.-The formation of the methine and carbon ions, J. Chem. Soc. Faraday Trans., 1956, 55, 876. [all data]

Tsuda and Hamill, 1964
Tsuda, S.; Hamill, W.H., Structure in ionization efficiency curves near threshold from alkanes and alkyl halides, J. Chem. Phys., 1964, 41, 2713. [all data]

Martin, Lampe, et al., 1966
Martin, R.H.; Lampe, F.W.; Taft, R.W., An electron-impact study of ionization and dissociation in methoxy- and halogen- substituted methanes, J. Am. Chem. Soc., 1966, 88, 1353. [all data]

Traeger and McLoughlin, 1981
Traeger, J.C.; McLoughlin, R.G., Absolute heats of formation for gas phase cations, J. Am. Chem. Soc., 1981, 103, 3647. [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]

Hierl, Henchman, et al., 1992
Hierl, P.M.; Henchman, M.J.; Paulson, J.F., Threshold Energies for the Reactions HO- + MeX - MeOH + X- measured by Tandem Mass Spectrometry: Acidities of MeCl and MeBr, Int. J. Mass Spectrom. Ion Proc., 1992, 117, 475, https://doi.org/10.1016/0168-1176(92)80109-E . [all data]

Ingemann and Nibbering, 1985
Ingemann, S.; Nibbering, N.M.M., Gas phase chemistry of alpha-thio carbanions, Can. J. Chem., 1985, 62, 2273. [all data]

Rogers, Simpson, et al., 2010
Rogers, N.J.; Simpson, M.J.; Tuckett, R.P.; Dunn, K.F.; Latimer, C.J., Vacuum-UV negative photoion spectroscopy of CH3F, CH3Cl and CH3Br, Phys. Chem. Chem. Phys., 2010, 12, 36, 10971-10980, https://doi.org/10.1039/c0cp00234h . [all data]

Ingemann and Nibbering, 1985, 2
Ingemann, S.; Nibbering, N.M.M., Gas-phase acidity of CH3X [X = P(CH3)2, SCH3, F, Cl, Br, I] compounds, J. Chem. Soc. Perkin Trans. 2, 1985, 837. [all data]


Notes

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