Home Symbol which looks like a small house Up Solid circle with an upward pointer in it

NOTICE: Due to scheduled maintenance at our Gaithersburg campus, this site will not be available from 5:00 pm EDT (21:00 UTC) on Friday October 25 until 5:00 pm (21:00 UTC) on Sunday October 27. We apologize for any inconvenience this outage may cause.

Methanethiol

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, Condensed phase thermochemistry data, Phase change data, Reaction 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 compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction 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 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
Deltafliquid-11.15 ± 0.13kcal/molCcrGood, Lacina, et al., 1961ALS
Quantity Value Units Method Reference Comment
Deltacliquid-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

Phase change data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction 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 compiled as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny, director
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
DH - Eugene S. Domalski and Elizabeth D. Hearing
CAL - James S. Chickos, William E. Acree, Jr., Joel F. Liebman, Students of Chem 202 (Introduction to the Literature of Chemistry), University of Missouri -- St. Louis

Quantity Value Units Method Reference Comment
Tboil279.1 ± 0.5KAVGN/AAverage of 6 values; Individual data points
Quantity Value Units Method Reference Comment
Tfus150.18KN/AMorris, Lanum, et al., 1960Uncertainty assigned by TRC = 0.02 K; TRC
Tfus150.1KN/ATeets, 1934Uncertainty assigned by TRC = 0.5 K; TRC
Tfus150.1KN/AEllis and Reid, 1932Uncertainty assigned by TRC = 0.4 K; TRC
Tfus152.15KN/ATimmermans and Mattaar, 1921Uncertainty assigned by TRC = 0.6 K; TRC
Quantity Value Units Method Reference Comment
Ttriple150.14KN/ARussell, Osborne, et al., 1942, 2Crystal phase 1 phase; Uncertainty assigned by TRC = 0.05 K; TRC
Ttriple150.16KN/ARussell, Osborne, et al., 1942, 2Crystal phase 1 phase; Uncertainty assigned by TRC = 0.03 K; TRC
Quantity Value Units Method Reference Comment
Tc469.9KN/ABerthoud and Brum, 1924Uncertainty assigned by TRC = 0.4 K; by disappearance of meniscus turbidity; TRC
Tc469.9KN/ABerthoud and Brum, 1924Uncertainty assigned by TRC = 0.4 K; by appearance of turbidity; TRC
Quantity Value Units Method Reference Comment
Pc71.35atmN/ABerthoud and Brum, 1924Uncertainty assigned by TRC = 0.5000 atm; vapor pressure at Tc; TRC
Quantity Value Units Method Reference Comment
rhoc6.891mol/lN/ABerthoud and Brum, 1924Uncertainty assigned by TRC = 0.04 mol/l; TRC
Quantity Value Units Method Reference Comment
Deltavap5.69kcal/molN/AReid, 1972AC
Deltavap5.69 ± 0.02kcal/molVGood, Lacina, et al., 1961ALS
Deltavap5.71kcal/molN/AGood, Lacina, et al., 1961DRB

Enthalpy of vaporization

DeltavapH (kcal/mol) Temperature (K) Method Reference Comment
5.8719279.12N/ARussell, Osborne, et al., 1942P = 101.325 kPa; DH
6.50223.N/ADykyj, Svoboda, et al., 1999Based on data from 208. - 298. K.; AC
6.02359.AStephenson and Malanowski, 1987Based on data from 267. - 359. K.; AC
6.14268.AStephenson and Malanowski, 1987Based on data from 221. - 283. K.; AC
5.66360.AStephenson and Malanowski, 1987Based on data from 345. - 424. K.; AC
5.78429.AStephenson and Malanowski, 1987Based on data from 414. - 470. K.; AC
6.17264.N/AStephenson and Malanowski, 1987Based on data from 222. - 279. K. See also Russell, Osborne, et al., 1942.; AC

Entropy of vaporization

DeltavapS (cal/mol*K) Temperature (K) Reference Comment
21.04279.12Russell, Osborne, et al., 1942P; DH

Antoine Equation Parameters

log10(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Temperature (K) A B C Reference Comment
279.9 - 458.4.348101122.494-21.748Stull, 1947Coefficents calculated by NIST from author's data.
221.87 - 279.134.186301031.431-32.72Russell, Osborne, et al., 1942Coefficents calculated by NIST from author's data.

Enthalpy of fusion

DeltafusH (kcal/mol) Temperature (K) Reference Comment
1.4150.2Domalski and Hearing, 1996AC

Entropy of fusion

DeltafusS (cal/mol*K) Temperature (K) Reference Comment
0.380137.6Domalski and Hearing, 1996CAL
9.400150.2

Enthalpy of phase transition

DeltaHtrs (kcal/mol) Temperature (K) Initial Phase Final Phase Reference Comment
0.05251137.6crystaline, IIcrystaline, IRussell, Osborne, et al., 1942DH
1.411150.16crystaline, IliquidRussell, Osborne, et al., 1942DH

Entropy of phase transition

DeltaStrs (cal/mol*K) Temperature (K) Initial Phase Final Phase Reference Comment
0.382137.6crystaline, IIcrystaline, IRussell, Osborne, et al., 1942DH
9.398150.16crystaline, IliquidRussell, Osborne, et al., 1942DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change 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 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 bullet Methanethiol)

By formula: F- + CH4S = (F- bullet CH4S)

Quantity Value Units Method Reference Comment
Deltar34.2 ± 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
Deltar23.2cal/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
Deltar27.3 ± 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
Deltar357.6 ± 2.0kcal/molD-EASchwartz, Davico, et al., 2000gas phase; B
Deltar357.5 ± 2.0kcal/molD-EAMoran and Ellison, 1988gas phase; B
Deltar356.9 ± 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
Deltar350.6 ± 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
Deltar395.3 ± 2.6kcal/molG+TSKass, Guo, et al., 1990gas phase; Acidity between D2O and Me2NH.; B
Deltar391.6 ± 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
Deltar388.2 ± 2.5kcal/molIMRBKass, Guo, et al., 1990gas phase; Acidity between D2O and Me2NH.; B

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

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

Quantity Value Units Method Reference Comment
Deltar7.8kcal/molPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; Entropy change calculated or estimated; M
Quantity Value Units Method Reference Comment
Deltar20.cal/mol*KN/AMeot-Ner (Mautner) and Sieck, 1985gas phase; Entropy change calculated or estimated; M

Free energy of reaction

DeltarG° (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 bullet Methanethiol)

By formula: Cl- + CH4S = (Cl- bullet CH4S)

Quantity Value Units Method Reference Comment
Deltar15.5 ± 3.0kcal/molIMRBStaneke, Groothuis, et al., 1995gas phase; Chloride affinity comparable to that of CHCl3; B
Quantity Value Units Method Reference Comment
Deltar10.8 ± 3.0kcal/molIMRBStaneke, Groothuis, et al., 1995gas phase; Chloride affinity comparable to that of CHCl3; B

MeCO2 anion + Methanethiol = (MeCO2 anion bullet Methanethiol)

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

Quantity Value Units Method Reference Comment
Deltar14.9 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Deltar22.8cal/mol*KPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Deltar8.1 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

(CH6N+ bullet Acetonitrile) + Methanethiol = (CH6N+ bullet Methanethiol bullet Acetonitrile)

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

Quantity Value Units Method Reference Comment
Deltar9.9kcal/molPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; M
Quantity Value Units Method Reference Comment
Deltar20.0cal/mol*KPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; M

CH6N+ + Methanethiol = (CH6N+ bullet Methanethiol)

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

Quantity Value Units Method Reference Comment
Deltar13.4kcal/molPHPMSMeot-Ner (Mautner) and Sieck, 1985gas phase; M
Quantity Value Units Method Reference Comment
Deltar22.1cal/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
Deltar-2.88 ± 0.54kcal/molEqkShum and Benson, 1983gas phase; ALS

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change 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 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).

View spectrum image in SVG format.

Download spectrum in JCAMP-DX format.

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 86

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, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry 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.

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]

Morris, Lanum, et al., 1960
Morris, J.C.; Lanum, W.J.; Helm, R.V.; Haines, W.E.; Cook, G.L.; Ball, J.S., Purification and Properties of Ten Organic Sulfur Compounds, J. Chem. Eng. Data, 1960, 5, 112-6. [all data]

Teets, 1934
Teets, D.E., The Relation of the Melting Point to the Number of Carbon Atoms in a Series of Normal Mercaptans, J. Am. Chem. Soc., 1934, 56, 1143. [all data]

Ellis and Reid, 1932
Ellis, L.M.; Reid, E.E., The Preparation and Properties of A Double Series of Aliphatic Mercaptans, J. Am. Chem. Soc., 1932, 54, 1674. [all data]

Timmermans and Mattaar, 1921
Timmermans, J.; Mattaar, J.F., Freezing points of orgainic substances VI. New experimental determinations., Bull. Soc. Chim. Belg., 1921, 30, 213. [all data]

Russell, Osborne, et al., 1942, 2
Russell, H.; 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, 165-9. [all data]

Berthoud and Brum, 1924
Berthoud, A.; Brum, R., Physical Properties of Some Organic Compounds., J. Chim. Phys. Phys.-Chim. Biol., 1924, 21, 143-60. [all data]

Reid, 1972
Reid, Robert C., Handbook on vapor pressure and heats of vaporization of hydrocarbons and related compounds, R. C. Wilhort and B. J. Zwolinski, Texas A Research Foundation. College Station, Texas(1971). 329 pages.$10.00, AIChE J., 1972, 18, 6, 1278-1278, https://doi.org/10.1002/aic.690180637 . [all data]

Dykyj, Svoboda, et al., 1999
Dykyj, J.; Svoboda, J.; Wilhoit, R.C.; Frenkel, M.L.; Hall, K.R., Vapor Pressure of Chemicals: Part A. Vapor Pressure and Antoine Constants for Hydrocarbons and Sulfur, Selenium, Tellurium and Hydrogen Containing Organic Compounds, Springer, Berlin, 1999, 373. [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [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]


Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), References