Methenium
Ion of carbon with three hydrogens
From Wikipedia, the free encyclopedia
In organic chemistry, methenium (also called methylium, carbenium,[2] methyl cation, or protonated methylene) is a cation with the 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 a carbocation and an enium ion, making it the simplest of the carbenium ions.[3]
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| Names | |||
|---|---|---|---|
| Preferred IUPAC name
Methylium[1] | |||
| Other names
Methyl cation; Carbanylium | |||
| Identifiers | |||
3D model (JSmol) |
|||
| 1839325 | |||
| ChEBI | |||
| ChemSpider | |||
| 48893 | |||
PubChem CID |
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| UNII | |||
CompTox Dashboard (EPA) |
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| Properties | |||
| CH3+ | |||
| Molar mass | 15.034 g·mol−1 | ||
| Related compounds | |||
Related isoelectronic |
borane | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure
Preparation and reactions
For mass spectrometry studies at low pressure, methenium can be obtained by ultraviolet photoionization of methyl radical,[3] or by collisions of monatomic cations such as C+
and Kr+
with neutral methane.[4] In such conditions, it will react with acetonitrile CH
3CN to form the ion (CH
3)
2CN+
.[5]
Upon capture of a low-energy electron (less than 1 eV), it will spontaneously dissociate.[6]
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 FSO3H-SbF5. The methenium ion is very reactive, even towards alkanes.[7]
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.[8][9]