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.

Methanediylium anion


Gas phase thermochemistry data

Go To: Top, Reaction thermochemistry data, Vibrational and/or electronic energy levels, 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

Quantity Value Units Method Reference Comment
Deltafgas328.3 ± 1.7kJ/molR-EALeopold, Murray, et al., 1985Singlet-triplet splitting of CH2 = 9.0 kcal
Deltafgas<328. ± 38.kJ/molEIAECollin and Locht, 1970From ketene
Deltafgas<290.0kJ/molEIAETrepka and Neuert, 1963From CH4

Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Vibrational and/or electronic energy levels, 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

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

CH2- + Hydrogen cation = Methyl cation

By formula: CH2- + H+ = CH3+

Quantity Value Units Method Reference Comment
Deltar1711.7 ± 1.7kJ/molD-EALeopold, Murray, et al., 1985gas phase; Singlet-triplet splitting of CH2 = 9.0 kcal
Quantity Value Units Method Reference Comment
Deltar1679.5 ± 2.0kJ/molH-TSLeopold, Murray, et al., 1985gas phase; Singlet-triplet splitting of CH2 = 9.0 kcal

Vibrational and/or electronic energy levels

Go To: Top, Gas phase thermochemistry 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: Marilyn E. Jacox

State:   A


 Energy 
 (cm-1
 Med.   Transition   «lambda»min 
 (nm) 
 «lambda»max 
 (nm) 
 References

Td = 5260 ± 50 gas Leopold, Murray, et al., 1985
Bunker and Sears, 1985

State:   X


Vib. 
sym. 
 No.   Approximate 
 type of mode 
 cm-1   Med.   Method   References

a1 2 Bend 1230 ± 30 gas PE Leopold, Murray, et al., 1985
Bunker and Sears, 1985

Additional references: Jacox, 1994, page 21

Notes

dPhotodissociation threshold

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Vibrational and/or electronic energy levels, Notes

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]

Bunker and Sears, 1985
Bunker, P.R.; Sears, T.J., Analysis of the laser photoelectron spectrum of CH-2, J. Chem. Phys., 1985, 83, 10, 4866, https://doi.org/10.1063/1.449747 . [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Vibrational and/or electronic energy levels, References