In organic chemistry, methenium (also called methylium, carbenium,[
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Structure
Experiments and calculations generally agree that the methenium ion is planar, with threefold symmetry.[ The carbon atom is a prototypical (and exact) example of sp2 hybridization.
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Preparation and reactions
For mass spectrometry studies at low pressure, methenium can be obtained by ultraviolet photoionization of methyl radical,[ or by collisions of monatomic cations such as and with neutral methane.][ In such conditions, it will react with acetonitrile to form the ion .][
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Upon capture of a low-energy electron (less than ), it will spontaneously dissociate.[
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It is seldom encountered as an intermediate in the condensed phase. It is proposed as a reactive intermediate that forms upon protonation or hydride abstraction of methane with Magic acid. The methenium ion is very reactive, even towards .
Detection
Origins of life
In June 2023, astronomers detected, for the first time outside the Solar System, methyl cation, CH3+ (and/or carbon cation, C+), the known basic ingredients of life, in interstellar space.
See also
