MeO anion
- Formula: CH3O-
- Molecular weight: 31.0345
- CAS Registry Number: 3315-60-4
- Information on this page:
- Other data available:
- Options:
Reaction 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.
Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
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
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 |
By formula: CH3O- + CH4O = (CH3O- • CH4O)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 29.3 ± 1.0 | kcal/mol | TDAs | Paul and Kebarle, 1990 | gas phase; B,M |
ΔrH° | 28.80 ± 0.30 | kcal/mol | TDAs | Meot-ner and Sieck, 1986 | gas phase; B,M |
ΔrH° | 29.4 ± 2.5 | kcal/mol | TDAs | Caldwell, Rozeboom, et al., 1984 | gas phase; Reanchored to average data from Paul and Kebarle, 1990 and Meot-ner and Sieck, 1986.; value altered from reference due to change in acidity scale; B |
ΔrH° | 19.0 ± 2.0 | kcal/mol | N/A | Moylan, Dodd, et al., 1985 | gas phase; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 31.8 | cal/mol*K | PHPMS | Paul and Kebarle, 1990 | gas phase; M |
ΔrS° | 26.7 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 20.30 | kcal/mol | IMRE | Mustanir, Matsuoka, et al., 2006 | gas phase; B |
ΔrG° | 19.8 ± 1.0 | kcal/mol | TDAs | Paul and Kebarle, 1990 | gas phase; B |
ΔrG° | 20.80 ± 0.50 | kcal/mol | TDAs | Meot-ner and Sieck, 1986 | gas phase; B |
ΔrG° | 20.3 ± 1.6 | kcal/mol | TDAs | Caldwell, Rozeboom, et al., 1984 | gas phase; Reanchored to average data from Paul and Kebarle, 1990 and Meot-ner and Sieck, 1986.; value altered from reference due to change in acidity scale; B |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
19.1 | 296. | FA | MacKay and Bohme, 1978 | gas phase; From thermochemical cycle,switching reaction(CH3O-)H2O; Meot-Ner(Mautner), 1986; M |
By formula: CH3O- + H2O = (CH3O- • H2O)
Bond type: Hydrogen bond (negative ion to hydride)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 25.3 ± 2.2 | kcal/mol | CIDT | DeTuri and Ervin, 1999 | gas phase; B |
ΔrH° | 23.9 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M,B,M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 22.9 | cal/mol*K | PHPMS | Meot-ner and Sieck, 1986 | gas phase; M |
ΔrS° | 22.9 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 17.00 ± 0.30 | kcal/mol | TDAs | Meot-ner and Sieck, 1986 | gas phase; B |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
15.4 | 296. | FA | MacKay and Bohme, 1978 | gas phase; From thermochemical cycle,switching reaction(OH-)H2O, DG>; Meot-Ner(Mautner), 1986; M |
(CH3O- • 4294967295) + = CH3O-
By formula: (CH3O- • 4294967295CH2O) + CH2O = CH3O-
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 39.90 ± 0.51 | kcal/mol | N/A | Nee, Osterwalder, et al., 2006 | gas phase; B |
ΔrH° | 40.8 ± 1.1 | kcal/mol | Ther | Osborn, Leahy, et al., 1998 | gas phase; B |
ΔrH° | 41.8 ± 2.2 | kcal/mol | Ther | 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 |
By formula: (CH3O- • 2H2O) + H2O = (CH3O- • 3H2O)
Bond type: Hydrogen bond (negative ion to hydride)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 14.8 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 24.4 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
7.9 | 296. | FA | MacKay and Bohme, 1978 | gas phase; From thermochemical cycle,switching reaction(OH-)3H2O; Meot-Ner(Mautner), 1986; M |
By formula: (CH3O- • H2O) + H2O = (CH3O- • 2H2O)
Bond type: Hydrogen bond (negative ion to hydride)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 19.2 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 25.3 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
8.2 | 296. | FA | MacKay and Bohme, 1978 | gas phase; From thermochemical cycle,switching reaction(OH-)2H2O; Meot-Ner(Mautner), 1986; M |
CH3O- + = C2H4D7O2-
By formula: CH3O- + CD4O = C2H4D7O2-
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 28.3 ± 1.0 | kcal/mol | IMRE | Chabinyc and Brauman, 2000 | gas phase; Original dG=19.4 at 350K; dS based on symmetry alone.; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 20.7 ± 1.0 | kcal/mol | IMRE | Chabinyc and Brauman, 2000 | gas phase; Original dG=19.4 at 350K; dS based on symmetry alone.; B |
(CH3O- • • ) + = (CH3O- • 2 • )
By formula: (CH3O- • H2O • CH4O) + H2O = (CH3O- • 2H2O • CH4O)
Bond type: Hydrogen bond (negative ion to hydride)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 15.2 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 27.7 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
By formula: (CH3O- • 2CH4O) + H2O = (CH3O- • H2O • 2CH4O)
Bond type: Hydrogen bond (negative ion to hydride)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 13.8 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 25.0 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
By formula: (CH3O- • CH4O) + H2O = (CH3O- • H2O • CH4O)
Bond type: Hydrogen bond (negative ion to hydride)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 17.8 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 25.9 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
By formula: (CH3O- • 3H2O) + H2O = (CH3O- • 4H2O)
Bond type: Hydrogen bond (negative ion to hydride)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 11.0 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 20.0 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
CH3O- + = C2H4F3O-
By formula: CH3O- + CHF3 = C2H4F3O-
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 23.5 ± 1.0 | kcal/mol | IMRE | Chabinyc and Brauman, 1998 | gas phase; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 16.6 ± 1.0 | kcal/mol | IMRE | Chabinyc and Brauman, 1998 | gas phase; B |
By formula: (CH3O- • H2O) + CH4O = (CH3O- • CH4O • H2O)
Free energy of reaction
ΔrG° (kcal/mol) | T (K) | Method | Reference | Comment |
---|---|---|---|---|
13.7 | 296. | FA | MacKay and Bohme, 1978 | gas phase; From thermochemical cycle,switching reaction(CH3O-)2H2O; Meot-Ner(Mautner), 1986; M |
By formula: CH3O- + BF3 = (CH3O- • BF3)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | >22.0 ± 2.0 | kcal/mol | IMRB | Blair, Isolani, et al., 1973 | gas phase; MeOH..MeO- + BF3 ->. Computations indicate dHaff ca. 80 kcal/mol; B |
By formula: (CH3O- • 2CH4O) + CH4O = (CH3O- • 3CH4O)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 15.0 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 26.3 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
By formula: (CH3O- • 3CH4O) + CH4O = (CH3O- • 4CH4O)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 11.4 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 22.4 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
By formula: (CH3O- • CH4O) + CH4O = (CH3O- • 2CH4O)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 21.4 | kcal/mol | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 27.8 | cal/mol*K | PHPMS | Meot-Ner(Mautner), 1986 | gas phase; n; M |
CH3O- + = C7H8F3OSi-
By formula: CH3O- + C6H5F3Si = C7H8F3OSi-
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 76.6 ± 5.9 | kcal/mol | CIDT | Krouse, Lardin, et al., 2003 | gas phase; B |
Gas phase ion energetics data
Go To: Top, 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: John E. Bartmess
Electron affinity of neutral species
EAneutral (eV) | Method | Reference | Comment |
---|---|---|---|
1.5690 ± 0.0019 | LPES | Nee, Osterwalder, et al., 2006 | |
1.5720 ± 0.0040 | LPES | Ramond, Davico, et al., 2000 | |
1.5680 ± 0.0050 | LPES | Osborn, Leahy, et al., 1998 | |
1.685 ± 0.094 | D-EA | Bartmess, Scott, et al., 1979 | 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 |
1.570 ± 0.022 | LPES | Engleking, Ellison, et al., 1978 | Confirmed by high level calculations: Hiraoka, Shimizu, et al., 1995 |
1.591 ± 0.040 | PD | Janousek, Zimmerman, et al., 1978 | |
<1.591 ± 0.039 | PD | Reed and Brauman, 1975 | |
2.59998 | EIAE | Tsuda and Hamill, 1964 | From MeOMe |
0.3816 | SI | Page and Goode, 1969 | The Magnetron method, lacking mass analysis, is not considered reliable. |
Protonation reactions
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 |
ΔrG° | 376.04 ± 0.55 | kcal/mol | H-TS | Osborn, Leahy, et al., 1998 | gas phase |
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 |
ΔrG° | 374.6 ± 2.1 | kcal/mol | H-TS | Haas and Harrison, 1993 | gas phase; Both metastable and 50 eV collision energy. |
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 |
References
Go To: Top, 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.
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]
Paul and Kebarle, 1990
Paul, G.J.C.; Kebarle, P.,
Thermodynamics of the Association Reactions OH- - H2O = HOHOH- and CH3O- - CH3OH = CH3OHOCH3- in the Gas Phase,
J. Phys. Chem., 1990, 94, 12, 5184, https://doi.org/10.1021/j100375a076
. [all data]
Caldwell, Rozeboom, et al., 1984
Caldwell, G.; Rozeboom, M.D.; Kiplinger, J.P.; Bartmess, J.E.,
Anion-alcohol hydrogen bond strengths in the gas phase,
J. Am. Chem. Soc., 1984, 106, 4660. [all data]
Moylan, Dodd, et al., 1985
Moylan, C.R.; Dodd, J.A.; Brauman, J.I.,
Electron photodetachment spectroscopy of Sslvated anions. A probe of structure and energetics,
Chem. Phys. Lett., 1985, 118, 38. [all data]
Meot-Ner(Mautner), 1986
Meot-Ner(Mautner), M.,
Comparative Stabilities of Cationic and Anionic Hydrogen-Bonded Networks. Mixed Clusters of Water-Methanol,
J. Am. Chem. Soc., 1986, 108, 20, 6189, https://doi.org/10.1021/ja00280a014
. [all data]
Mustanir, Matsuoka, et al., 2006
Mustanir; Matsuoka, M.; Mishima, M.; Koch, H.,
Stability of complexes of phenylacetylides and benzyl alkoxides with methanol in the gas phase. Acid-base correlation in the ionic hydrogen-bond strength,
Bull. Chem. Soc. Japan, 2006, 79, 7, 1118-1125, https://doi.org/10.1246/bcsj.79.1118
. [all data]
MacKay and Bohme, 1978
MacKay, G.I.; Bohme, D.K.,
Proton-Transfer Reactions in Nitromethane at 297K,
Int. J. Mass Spectrom. Ion Phys., 1978, 26, 4, 327, https://doi.org/10.1016/0020-7381(78)80052-7
. [all data]
DeTuri and Ervin, 1999
DeTuri, V.F.; Ervin, K.M.,
Competitive threshold collision-induced dissociation: Gas-phase acidities and bond dissociation energies for a series of alcohols,
J. Phys. Chem. A, 1999, 103, 35, 6911-6920, https://doi.org/10.1021/jp991459m
. [all data]
Chabinyc and Brauman, 2000
Chabinyc, M.L.; Brauman, J.I.,
Unusual ionic hydrogen bonds: Complexes of acetylides and fluoroform,
J. Am. Chem. Soc., 2000, 122, 36, 8739-8745, https://doi.org/10.1021/ja000806z
. [all data]
Chabinyc and Brauman, 1998
Chabinyc, M.L.; Brauman, J.I.,
Acidity, basicity, and the stability of hydrogen bonds: Complexes of RO-+HCF3,
J. Am. Chem. Soc., 1998, 120, 42, 10863-10870, https://doi.org/10.1021/ja9817592
. [all data]
Blair, Isolani, et al., 1973
Blair, L.K.; Isolani, P.C.; Riveros, J.M.,
Formation, reactivity, and relative stability of clustered alkoxide ions by ICR spectroscopy,
J. Am. Chem. Soc., 1973, 95, 1057. [all data]
Krouse, Lardin, et al., 2003
Krouse, I.H.; Lardin, H.A.; Wenthold, P.G.,
Gas-phase ion chemistry and ion thermochemistry of phenyltrifluorosilane,
Int. J. Mass Spectrom., 2003, 227, 3, 303-314, https://doi.org/10.1016/S1387-3806(03)00080-0
. [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, 1158-1169, https://doi.org/10.1063/1.480767
. [all data]
Engleking, Ellison, et al., 1978
Engleking, P.C.; Ellison, G.B.; Lineberger, W.C.,
Laser photodetachment electron spectrometry of methoxide, deuteromethoxide, and thiomethoxide: Electron affinities and vibrational structure of CH3O, and CH3S,
J. Chem. Phys., 1978, 69, 1826. [all data]
Hiraoka, Shimizu, et al., 1995
Hiraoka, K.; Shimizu, A.; Minamitsu, A.; Nasu, M.; Fujimaki, S.; Yamabe, S.,
The small binding energies of the negative cluster ions: SF5-(SF6)1, SF6-(SF6)1 and F-(SF6)n (n=1 and 2), in the gas phase,
Chem. Phys. Lett., 1995, 241, 5-6, 623, https://doi.org/10.1016/0009-2614(95)00676-U
. [all data]
Janousek, Zimmerman, et al., 1978
Janousek, B.K.; Zimmerman, A.H.; Reed, K.J.; Brauman, J.I.,
Electron detachment from aliphatic molecular anions. Gas phase electron affinites of methoxyl, tert-butoxyl, and neopentoxyl radicals,
J. Am. Chem. Soc., 1978, 100, 6142. [all data]
Reed and Brauman, 1975
Reed, K.J.; Brauman, J.I.,
Electron affinities of alkoxy radicals and the bond dissociation energies in aliphatic alcohols,
J. Am. Chem. Soc., 1975, 97, 1625. [all data]
Tsuda and Hamill, 1964
Tsuda, S.; Hamill, W.H.,
Ionization Efficiency Measurements by the Retarding Potential Difference Method,
Adv. Mass Spectrom., 1964, 3, 249. [all data]
Page and Goode, 1969
Page, F.M.; Goode, G.C.,
Negative Ions and the Magnetron., Wiley, NY, 1969. [all data]
Notes
Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
EAneutral Electron affinity of neutral species T Temperature ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
- The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.