MeO anion
- Formula: CH3O-
- Molecular weight: 31.0345
- CAS Registry Number: 3315-60-4
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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
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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 |
References
Go To: Top, Reaction thermochemistry 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]
Notes
Go To: Top, Reaction thermochemistry data, References
- Symbols used in this document:
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
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