Methenium
In organic chemistry, methenium (also called methylium, methyl cation or protonated methylene) is a positive ion with formula CH+
3. It can be viewed as a methylene radical (:CH
2) with an added proton (H+
), or as a methyl radical (•CH
3) with one electron removed. It is one of the simplest carbocations, indeed the simplest carbenium ion, and an enium ion.[1]
Structure
The methenium ion is planar or nearly planar, with threefold symmetry.[1]
Preparation
For mass spectroscopy studies at low pressure, methenium can be obtained by ultraviolet photoionization of methyl radical,[1] or by collisions of monoatomic cations like C+
and Kr+
with neutral methane.[2]
References
- ^ a b c L. Golob, N. Jonathan, A. Morris, M. Okuda, K.J. Ross (1972), "The first ionization potential of the methyl radical as determined by photoelectron spectroscopy". Journal of Electron Spectroscopy and Related Phenomena, volume 1, issue 5, pages 506-508 doi:10.1016/0368-2048(72)80022-7
- ^ R. B. Sharma , N. M. Semo , W. S. Koski (1987), "Dynamics of the reactions of methylium, methylene radical cation, and methyliumylidene with acetylene". Journal of Physical Chemistry, volume 91 issue 15, pages 4127–4131 doi:10.1021/j100299a037