Methanethiol

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Gas phase thermochemistry 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: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Δfgas-5.46 ± 0.14kcal/molCcrGood, Lacina, et al., 1961 

Condensed phase thermochemistry 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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Δfliquid-11.15 ± 0.13kcal/molCcrGood, Lacina, et al., 1961ALS
Quantity Value Units Method Reference Comment
Δcliquid-363.47 ± 0.12kcal/molCcrGood, Lacina, et al., 1961Reanalyzed by Cox and Pilcher, 1970, Original value = -363.0 ± 0.12 kcal/mol; ALS
Quantity Value Units Method Reference Comment
liquid39.011cal/mol*KN/ARussell, Osborne, et al., 1942DH

Constant pressure heat capacity of liquid

Cp,liquid (cal/mol*K) Temperature (K) Reference Comment
21.28280.Russell, Osborne, et al., 1942T = 15 to 280 K.; DH

Reaction thermochemistry 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
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

Fluorine anion + Methanethiol = (Fluorine anion • Methanethiol)

By formula: F- + CH4S = (F- • CH4S)

Quantity Value Units Method Reference Comment
Δr34.2 ± 2.0kcal/molIMRELarson and McMahon, 1983gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M
Quantity Value Units Method Reference Comment
Δr23.2cal/mol*KN/ALarson and McMahon, 1983gas phase; switching reaction(F-)H2O, Entropy change calculated or estimated; Arshadi, Yamdagni, et al., 1970; M
Quantity Value Units Method Reference Comment
Δr27.3 ± 2.0kcal/molIMRELarson and McMahon, 1983gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M

MeS anion + Hydrogen cation = Methanethiol

By formula: CH3S- + H+ = CH4S

Quantity Value Units Method Reference Comment
Δr357.6 ± 2.0kcal/molD-EASchwartz, Davico, et al., 2000gas phase; B
Δr357.5 ± 2.0kcal/molD-EAMoran and Ellison, 1988gas phase; B
Δr356.9 ± 2.2kcal/molG+TSBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B
Quantity Value Units Method Reference Comment
Δr350.6 ± 2.0kcal/molIMREBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B

CH3S- + Hydrogen cation = Methanethiol

By formula: CH3S- + H+ = CH4S

Quantity Value Units Method Reference Comment
Δr395.3 ± 2.6kcal/molG+TSKass, Guo, et al., 1990gas phase; Acidity between D2O and Me2NH.; B
Δr391.6 ± 7.7kcal/molD-EAKass, Guo, et al., 1990gas phase; Between O2 and SO2. Explains bad anchor in McIver Jr. and Fukuda, 1982; B
Quantity Value Units Method Reference Comment
Δr388.2 ± 2.5kcal/molIMRBKass, Guo, et al., 1990gas phase; Acidity between D2O and Me2NH.; B

(CH6N+ • 2Acetonitrile) + Methanethiol = (CH6N+ • Methanethiol • 2Acetonitrile)

By formula: (CH6N+ • 2C2H3N) + CH4S = (CH6N+ • CH4S • 2C2H3N)

Quantity Value Units Method Reference Comment
Δr7.8kcal/molPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; Entropy change calculated or estimated; M
Quantity Value Units Method Reference Comment
Δr20.cal/mol*KN/AMeot-Ner (Mautner) and Sieck, 1985gas phase; Entropy change calculated or estimated; M

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
2.4270.PHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; Entropy change calculated or estimated; M

Chlorine anion + Methanethiol = (Chlorine anion • Methanethiol)

By formula: Cl- + CH4S = (Cl- • CH4S)

Quantity Value Units Method Reference Comment
Δr15.5 ± 3.0kcal/molIMRBStaneke, Groothuis, et al., 1995gas phase; Chloride affinity comparable to that of CHCl3; B
Quantity Value Units Method Reference Comment
Δr10.8 ± 3.0kcal/molIMRBStaneke, Groothuis, et al., 1995gas phase; Chloride affinity comparable to that of CHCl3; B

MeCO2 anion + Methanethiol = (MeCO2 anion • Methanethiol)

By formula: C2H3O2- + CH4S = (C2H3O2- • CH4S)

Quantity Value Units Method Reference Comment
Δr14.9 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Δr22.8cal/mol*KPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr8.1 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

(CH6N+ • Acetonitrile) + Methanethiol = (CH6N+ • Methanethiol • Acetonitrile)

By formula: (CH6N+ • C2H3N) + CH4S = (CH6N+ • CH4S • C2H3N)

Quantity Value Units Method Reference Comment
Δr9.9kcal/molPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; M
Quantity Value Units Method Reference Comment
Δr20.0cal/mol*KPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; M

CH6N+ + Methanethiol = (CH6N+ • Methanethiol)

By formula: CH6N+ + CH4S = (CH6N+ • CH4S)

Quantity Value Units Method Reference Comment
Δr13.4kcal/molPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; M
Quantity Value Units Method Reference Comment
Δr22.1cal/mol*KPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; M

Hydrogen iodide + Methylsulfenyliodide = Methanethiol + Iodine

By formula: HI + CH3IS = CH4S + I2

Quantity Value Units Method Reference Comment
Δr-2.88 ± 0.54kcal/molEqkShum and Benson, 1983gas phase; ALS

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction 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:
HL - Edward P. Hunter and Sharon G. Lias
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
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 CH4S+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)9.439 ± 0.005eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)184.8kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity177.kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Δf(+) ion213. ± 2.kcal/molN/AN/A 
Quantity Value Units Method Reference Comment
ΔfH(+) ion,0K215. ± 2.kcal/molN/AN/A 

Ionization energy determinations

IE (eV) Method Reference Comment
9.446 ± 0.010PINourbakhsh, Norwood, et al., 1991LL
9.4386PIKutina, Edwards, et al., 1982T = 0K; LBLHLM
9.46PEKimura, Katsumata, et al., 1981LLK
9.44PEOgata, Onizuka, et al., 1973LLK
9.44PEOgata, Onizuka, et al., 1972LLK
9.415PEKroto and Suffolk, 1972LLK
9.42PEFrost, Herring, et al., 1972LLK
9.44 ± 0.01PIAkopyan, Sergeev, et al., 1970RDSH
9.440 ± 0.005PIWatanabe, Nakayama, et al., 1962RDSH
9.443 ± 0.002SPrice, Teegan, et al., 1950RDSH
9.44PECradock and Whiteford, 1972Vertical value; LLK
9.44PEBock, Wagner, et al., 1972Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CHS+≤13.55 ± 0.04H+H2PIKutina, Edwards, et al., 1982LBLHLM
CHS+≤13.61 ± 0.04H+H2PIKutina, Edwards, et al., 1982T = 0K; LBLHLM
CHS+15.8 ± 0.5?EIRuska and Franklin, 1969RDSH
CH2S+10.58 ± 0.05H2PINourbakhsh, Norwood, et al., 1991LL
CH2S+10.61 ± 0.05H2PIKutina, Edwards, et al., 1982T = 0K; LBLHLM
CH2S+10.55 ± 0.05H2PIKutina, Edwards, et al., 1982LBLHLM
CH2S+10.8 ± 0.1H2PIAkopyan, Sergeev, et al., 1970RDSH
CH2S+[HCSH+]~11.51H2PIKutina, Edwards, et al., 1982LBLHLM
CH2S+[HCSH+]~11.57H2PIKutina, Edwards, et al., 1982T = 0K; LBLHLM
CH3+13.296 ± 0.021SHPIKutina, Edwards, et al., 1982LBLHLM
CH3+13.357 ± 0.021SHPIKutina, Edwards, et al., 1982T = 0K; LBLHLM
CH3S+11.23 ± 0.05HPINourbakhsh, Norwood, et al., 1991LL
CH3S+11.48 ± 0.05HEIHolmes, Lossing, et al., 1983LBLHLM
CH3S+11.550 ± 0.005HPIKutina, Edwards, et al., 1982LBLHLM
CH3S+11.611 ± 0.005HPIKutina, Edwards, et al., 1982T = 0K; LBLHLM
CH3S+11.37 ± 0.05HPIAkopyan, Sergeev, et al., 1970RDSH
CH3S+11.6 ± 0.1HEITaft, Martin, et al., 1965RDSH

De-protonation reactions

MeS anion + Hydrogen cation = Methanethiol

By formula: CH3S- + H+ = CH4S

Quantity Value Units Method Reference Comment
Δr357.6 ± 2.0kcal/molD-EASchwartz, Davico, et al., 2000gas phase; B
Δr357.5 ± 2.0kcal/molD-EAMoran and Ellison, 1988gas phase; B
Δr356.9 ± 2.2kcal/molG+TSBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B
Quantity Value Units Method Reference Comment
Δr350.6 ± 2.0kcal/molIMREBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B

CH3S- + Hydrogen cation = Methanethiol

By formula: CH3S- + H+ = CH4S

Quantity Value Units Method Reference Comment
Δr395.3 ± 2.6kcal/molG+TSKass, Guo, et al., 1990gas phase; Acidity between D2O and Me2NH.; B
Δr391.6 ± 7.7kcal/molD-EAKass, Guo, et al., 1990gas phase; Between O2 and SO2. Explains bad anchor in McIver Jr. and Fukuda, 1982; B
Quantity Value Units Method Reference Comment
Δr388.2 ± 2.5kcal/molIMRBKass, Guo, et al., 1990gas phase; Acidity between D2O and Me2NH.; B

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction 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.

Good, Lacina, et al., 1961
Good, W.D.; Lacina, J.L.; McCullough, J.P., Methanethiol and carbon disulfide: Heats of combustion and formation by rotating-bomb calorimetry, J. Phys. Chem., 1961, 65, 2229-2231. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Russell, Osborne, et al., 1942
Russell, H., Jr.; Osborne, D.W.; Yost, D.M., The heat capacity, entropy, heats of fusion, transition, and vaporization and vapor pressures of methyl mercaptan, J. Am. Chem. Soc., 1942, 64, 165-169. [all data]

Larson and McMahon, 1983
Larson, J.W.; McMahon, T.B., Strong hydrogen bonding in gas-phase anions. An ion cyclotron resonance determination of fluoride binding energetics to bronsted acids from gas-phase fluoride exchange equilibria measurements, J. Am. Chem. Soc., 1983, 105, 2944. [all data]

Wenthold and Squires, 1995
Wenthold, P.G.; Squires, R.R., Bond dissociation energies of F2(-) and HF2(-). A gas-phase experimental and G2 theoretical study, J. Phys. Chem., 1995, 99, 7, 2002, https://doi.org/10.1021/j100007a034 . [all data]

Arshadi, Yamdagni, et al., 1970
Arshadi, M.; Yamdagni, R.; Kebarle, P., Hydration of Halide Negative Ions in the Gas Phase. II. Comparison of Hydration Energies for the Alkali Positive and Halide Negative Ions, J. Phys. Chem., 1970, 74, 7, 1475, https://doi.org/10.1021/j100702a014 . [all data]

Schwartz, Davico, et al., 2000
Schwartz, R.L.; Davico, G.E.; Lineberger, W.C., Negative-ion photoelectron spectroscopy of CH3S-, J. Electron Spectros. Rel. Phenom., 2000, 108, 1-3, 163-168, https://doi.org/10.1016/S0368-2048(00)00125-0 . [all data]

Moran and Ellison, 1988
Moran, S.; Ellison, G.B., Photoelectron Spectroscopy of Sulfur Ions, J. Phys. Chem., 1988, 92, 7, 1794, https://doi.org/10.1021/j100318a021 . [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]

Kass, Guo, et al., 1990
Kass, S.R.; Guo, H.-Z.; Dahlke, G.D., The Thiomethyl Anion: Formation, Reactivity, and Thermodynamic Properties, J. Am. Soc. Mass Spectrom., 1990, 1, 5, 366, https://doi.org/10.1016/1044-0305(90)85016-F . [all data]

McIver Jr. and Fukuda, 1982
McIver Jr.; Fukuda, E.K., Equilibrium Electron Affinities, Lec. Notes in Chem., 1982, 31, 165. [all data]

Meot-Ner (Mautner) and Sieck, 1985
Meot-Ner (Mautner), M.; Sieck, L.W., The Ionic Hydrogen Bond and Ion Solvation. 4. SH+ O and NH+ S Bonds. Correlations with Proton Affinity. Mutual Effects of Weak and Strong Ligands in Mixed Clusters, J. Phys. Chem., 1985, 89, 24, 5222, https://doi.org/10.1021/j100270a021 . [all data]

Staneke, Groothuis, et al., 1995
Staneke, P.O.; Groothuis, G.; Ingemann, S.; Nibbering, N.M.M., Formation, stability and structure of radical anions of chloroform, tetrachloromethane and fluorotrichloromethane in the gas phase, Int. J. Mass Spectrom. Ion Proc., 1995, 142, 1-2, 83, https://doi.org/10.1016/0168-1176(94)04127-S . [all data]

Meot-ner, 1988
Meot-ner, M., Ionic Hydrogen Bond and Ion Solvation. 6. Interaction Energies of the Acetate Ion with Organic Molecules. Comparison of CH3COO- with Cl-, CN-, and SH-, J. Am. Chem. Soc., 1988, 110, 12, 3854, https://doi.org/10.1021/ja00220a022 . [all data]

Shum and Benson, 1983
Shum, L.G.S.; Benson, S.W., Thermochemnistry and kinetics of the reaction of methyl mercaptan with iodine, Int. J. Chem. Kinet., 1983, 15, 433-453. [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]

Nourbakhsh, Norwood, et al., 1991
Nourbakhsh, S.; Norwood, K.; Yin, H.-M.; Liao, C.-L.; Ng, C.Y., Vacuum ultraviolet photodissociation and photoionization studies of CH3SH and SH, J. Chem. Phys., 1991, 95, 946. [all data]

Kutina, Edwards, et al., 1982
Kutina, R.; Edwards, A.; Goodman, G.; Berkowitz, J., Photoionization mass spectrometry of CH3SH, CD3SH, and CH3SD: Heats of formation of CH3S+ (CH2SH+), CH2S+, CH2S, and HCS+, J. Chem. Phys., 1982, 77, 5508. [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]

Ogata, Onizuka, et al., 1973
Ogata, H.; Onizuka, H.; Nihei, Y.; Kamada, H., The photoelectron spectra of alcohols, mercaptans and amines, Bull. Chem. Soc. Jpn., 1973, 46, 3036. [all data]

Ogata, Onizuka, et al., 1972
Ogata, H.; Onizuka, H.; Nihei, Y.; Kamada, H., On the first bands of the photoelectron spectra of amines, alcohols, and mercaptans, Chem. Lett., 1972, 895. [all data]

Kroto and Suffolk, 1972
Kroto, H.W.; Suffolk, R.J., The photoelectron spectrum of an unstable species in the pyrolysis products of dimethyldisulphide, Chem. Phys. Lett., 1972, 15, 545. [all data]

Frost, Herring, et al., 1972
Frost, D.C.; Herring, F.G.; Katrib, A.; McDowell, C.A.; McLean, R.A.N., Photoelectron spectra of CH3SH, (CH3)2S, C6H5SH, and C6H5CH2SH; the bonding between sulfur and carbon, J. Phys. Chem., 1972, 76, 1030. [all data]

Akopyan, Sergeev, et al., 1970
Akopyan, M.E.; Sergeev, Yu.L.; Vilesov, F.I., Photionization in vapors of aliphatic sulfides. I. Methymercaptan, dimethyl and diethyl sulfides, High Energy Chem., 1970, 4, 265, In original 305. [all data]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Price, Teegan, et al., 1950
Price, W.C.; Teegan, J.P.; Walsh, A.D., The far ultra-violet absorption spectra of the hydrides and deuterides of sulphur, selenium and tellurium and of the methyl derivatives of hydrogen sulphide, Proc. Roy. Soc. (London), 1950, A201, 600. [all data]

Cradock and Whiteford, 1972
Cradock, S.; Whiteford, R.A., Photoelectron spectra of the methyl, silyl and germyl derivatives of the group VI elements, J. Chem. Soc. Faraday Trans. 2, 1972, 68, 281. [all data]

Bock, Wagner, et al., 1972
Bock, H.; Wagner, G.; Kroner, J., Photoelektronenspektren und molekuleigenschaften, XIV. Die delokalisation des schwefel-elektronenpaar in CH3S-substituierten aromaten, Chem. Ber., 1972, 105, 3850. [all data]

Ruska and Franklin, 1969
Ruska, W.E.W.; Franklin, J.L., Ion-molecule reactions in hydrogen sulfide, methanethiol and 2-thiapropane, Intern. J. Mass Spectrom. Ion Phys., 1969, 3, 221. [all data]

Holmes, Lossing, et al., 1983
Holmes, J.L.; Lossing, F.P.; Terlouw, J.K.; Burgers, P.C., Novel gas-phase ions. The radical cations [CH2XH]+. (X = F, Cl, Br, I, OH, NH2, SH) and [CH2CH2NH3]+., Can. J. Chem., 1983, 61, 2305. [all data]

Taft, Martin, et al., 1965
Taft, R.W.; Martin, R.H.; Lampe, F.W., Stabilization energies of substituted methyl cations. The effect of strong demand on the resonance order, J. Am. Chem. Soc., 1965, 87, 2490. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, References