Methanediylium anion
- Formula: CH2-
- Molecular weight: 14.0271
- CAS Registry Number: 50928-07-9
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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: John E. Bartmess
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | 328.3 ± 1.7 | kJ/mol | R-EA | Leopold, Murray, et al., 1985 | Singlet-triplet splitting of CH2 = 9.0 kcal |
| ΔfH°gas | <328. ± 38. | kJ/mol | EIAE | Collin and Locht, 1970 | From ketene |
| ΔfH°gas | <290.0 | kJ/mol | EIAE | Trepka and Neuert, 1963 | From CH4 |
Gas phase ion energetics data
Go To: Top, Gas phase 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
Protonation reactions
CH2- + =
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 1711.7 ± 1.7 | kJ/mol | D-EA | Leopold, Murray, et al., 1985 | gas phase; Singlet-triplet splitting of CH2 = 9.0 kcal |
| Quantity | Value | Units | Method | Reference | Comment |
| ΔrG° | 1679.5 ± 2.0 | kJ/mol | H-TS | Leopold, Murray, et al., 1985 | gas phase; Singlet-triplet splitting of CH2 = 9.0 kcal |
References
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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Leopold, Murray, et al., 1985
Leopold, D.G.; Murray, K.K.; Miller, A.E.S.; Lineberger, W.C.,
Methylene: A study of the X3B1 and the 1A1 states by photoelectron spectroscopy of CH2- and CD2-,
J. Chem. Phys., 1985, 83, 4849. [all data]
Collin and Locht, 1970
Collin, J.E.; Locht, R.,
Positive and negative ion formation in ketene by electron impact,
Intern. J. Mass Spectrom. Ion Phys., 1970, 3, 465. [all data]
Trepka and Neuert, 1963
Trepka, L.v.; Neuert, H.,
Uber die Entstehenung von Negativen Ionen aus einigen Kohlenwasserstoffen und Alkoholen durch Elektronenstoss,
Z. Naturfor., 1963, 18A, 1295. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
ΔfH°gas Enthalpy of formation of gas at standard conditions ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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