EtO anion

Formula: C₂H₅O^-
Molecular weight: 45.0610
CAS Registry Number: 16331-64-9
Information on this page:
Other data available:
- Gas phase ion energetics data
- Ion clustering data
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Reaction thermochemistry data

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

C₂H₅O^- + = (C₂H₅O^- )

By formula: C₂H₅O^- + C₂H₆O = (C₂H₅O^- C₂H₆O)

Quantity	Value	Units	Method	Reference	Comment
_rH°	115. ± 4.2	kJ/mol	TDEq	Meot-Ner and Sieck, 1986	gas phase; B,M
_rH°	118. ± 10.	kJ/mol	N/A	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,M
Quantity	Value	Units	Method	Reference	Comment
_rS°	112.	J/mol*K	PHPMS	Meot-Ner and Sieck, 1986	gas phase; M
_rS°	123.	J/mol*K	N/A	Caldwell, Rozeboom, et al., 1984	gas phase; switching reaction(CH3O-)CH3OH; Entropy change calculated or estimated; re-evaluated using Meot-Ner(Mautner), 1986 and Paul and Kebarle, 1990; M
Quantity	Value	Units	Method	Reference	Comment
_rG°	82.0 ± 6.7	kJ/mol	TDEq	Meot-Ner and Sieck, 1986	gas phase; B
_rG°	79.5 ± 6.7	kJ/mol	IMRE	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,M
_rG°	84.1	kJ/mol	ICR	McIver, Scott, et al., 1973	gas phase; switching reaction(CH3O-)CH3OH, Entropy change calculated or estimated; Meot-Ner (Mautner), 1992; M

C₂H₅O^- + = (C₂H₅O^- )

By formula: C₂H₅O^- + CH₄O = (C₂H₅O^- CH₄O)

Quantity	Value	Units	Method	Reference	Comment
_rH°	114. ± 12.	kJ/mol	IMRE	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,M
_rH°	107. ± 7.9	kJ/mol	CIDT	DeTuri and Ervin, 1999	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
_rS°	123.	J/mol*K	N/A	Caldwell, Rozeboom, et al., 1984	gas phase; switching reaction(CH3O-)CH3OH, Entropy change calculated or estimated; re-evaluated using Meot-Ner(Mautner), 1986 and Paul and Kebarle, 1990; M
Quantity	Value	Units	Method	Reference	Comment
_rG°	77.8 ± 8.4	kJ/mol	IMRE	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,M

Free energy of reaction

_rG° (kJ/mol)	T (K)	Method	Reference	Comment
56.1	296.	FA	Mackay, Rakshit, et al., 1982	gas phase; From thermochemical cycle,switching reaction(CH3O-)CH3OH; Caldwell and Kebarle, 1986, Taft, 1983; M

C₂H₅O^- + =

By formula: C₂H₅O^- + H⁺ = C₂H₆O

Quantity	Value	Units	Method	Reference	Comment
_rH°	1587. ± 4.2	kJ/mol	D-EA	Ramond, Davico, et al., 2000	gas phase; B
_rH°	1582. ± 8.4	kJ/mol	CIDC	Haas and Harrison, 1993	gas phase; Both metastable and 50 eV collision energy.; B
_rH°	1579. ± 8.8	kJ/mol	G+TS	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B
_rH°	1586.2 ± 0.42	kJ/mol	CIDT	DeTuri and Ervin, 1999	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
_rG°	1559. ± 4.6	kJ/mol	H-TS	Ramond, Davico, et al., 2000	gas phase; B
_rG°	1554. ± 8.8	kJ/mol	H-TS	Haas and Harrison, 1993	gas phase; Both metastable and 50 eV collision energy.; B
_rG°	1551. ± 8.4	kJ/mol	IMRE	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B

(C₂H₅O^- 4294967295) + = C₂H₅O^-

By formula: (C₂H₅O^- 4294967295C₂H₄O) + C₂H₄O = C₂H₅O^-

Quantity	Value	Units	Method	Reference	Comment
_rH°	158. ± 4.2	kJ/mol	N/A	Ramond, Davico, et al., 2000	gas phase; B
_rH°	165. ± 9.2	kJ/mol	Ther	Bartmess, Scott, et al., 1979	gas phase; value altered from reference due to change in acidity scale; B

C₂H₅O^- + = C₃H₆F₃O^-

By formula: C₂H₅O^- + CHF₃ = C₃H₆F₃O^-

Quantity	Value	Units	Method	Reference	Comment
_rH°	92.0 ± 4.2	kJ/mol	IMRE	Chabinyc and Brauman, 1998	gas phase; B
Quantity	Value	Units	Method	Reference	Comment
_rG°	63.2 ± 4.2	kJ/mol	IMRE	Chabinyc and Brauman, 1998	gas phase; B

References

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Meot-Ner and Sieck, 1986
Meot-Ner, M.; Sieck, L.W., The ionic hydrogen bond and ion solvation. 5. OH...O^- bonds. Gas phase solvation and clustering of alkoxide and carboxylate anions, J. Am. Chem. Soc., 1986, 108, 7525. [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]

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]

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]

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]

McIver, Scott, et al., 1973
McIver, R.T., Jr.; Scott, J.A.; Riveros, J.M., Effect of solvation on the intrinsic relative acidity of methanol and ethanol, J. Am. Chem. Soc., 1973, 95, 2706. [all data]

Meot-Ner (Mautner), 1992
Meot-Ner (Mautner), M., Intermolecular Forces in Organic Clusters, J. Am. Chem. Soc., 1992, 114, 9, 3312, https://doi.org/10.1021/ja00035a024 . [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]

Mackay, Rakshit, et al., 1982
Mackay, G.I.; Rakshit, A.B.; Bohme, D.K., An Experimental Study of the Reactivity and Relative Basicity of the Methoxide Anion in the Gas Phase at Room Temperature, and their Perturbation by Methanol Solvent, Can. J. Chem., 1982, 60, 20, 2594, https://doi.org/10.1139/v82-373 . [all data]

Caldwell and Kebarle, 1986
Caldwell, G.; Kebarle, P., Mobility of Gaseous Ions in Weak Electric Fields in Unpublished results, 1986. [all data]

Taft, 1983
Taft, R.W., Protonic acidities and basicities in the gas phase and in solution: Substiuent and solvent effects, Prog. Phys. Org. Chem., 1983, 14, 247. [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]

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]

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]

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]

Notes

Go To: Top, Reaction thermochemistry data, References

Symbols used in this document:

T Temperature

_rG° Free energy of reaction at standard conditions

_rH° Enthalpy of reaction at standard conditions

_rS° Entropy of reaction at standard conditions
Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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T	Temperature
_rG°	Free energy of reaction at standard conditions
_rH°	Enthalpy of reaction at standard conditions
_rS°	Entropy of reaction at standard conditions