 "True" methanium, the metastable transitional state [CH5]+
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 Fluxional methanium, [CH3(H2)]+
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| Names | |
|---|---|
| IUPAC name
Methanium
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| Other names
carbonium (discouraged due to multiple definitions)[1]
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| Identifiers | |
3D model (JSmol)
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PubChem CID
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| Properties | |
| CH+5 | |
| Molar mass | 17.051 g·mol−1 |
| Conjugate base | Methane |
| Structure | |
| trigonal bipyramidal | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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In chemistry, methanium is a complex positive ion with formula [CH5]+ (metastable transitional form, a carbon atom covalently bonded to five hydrogen atoms) or [CH3(H2)]+ (fluxional form, namely a molecule with one carbon atom covalently bonded to three hydrogen atoms and one dihydrogen molecule), bearing a +1 electric charge. It is a superacid and one of the onium ions, indeed the simplest carbonium ion.
It is highly unstable and highly reactive even upon having a complete octet, thus granting its superacidic properties.
Methanium can be produced in the laboratory as a rarefied gas or as a dilute species in superacids. It was prepared for the first time in 1950 and published in 1952 by Victor Talrose and his assistant Anna Konstantinovna Lyubimova.[2][3] It occurs as an intermediate species in chemical reactions.
The methanium ion is named after methane (CH4), by analogy with the derivation of ammonium ion (NH+4) from ammonia (NH3).
- ^ Chemistry, International Union of Pure and Applied (2009). "carbonium ion". IUPAC Compendium of Chemical Terminology. IUPAC. doi:10.1351/goldbook.C00839. ISBN 978-0-9678550-9-7. Retrieved 27 November 2018.
- ^ Cite error: The named reference
Talrosewas invoked but never defined (see the help page). - ^ Nikolaev, Eugene (1998). "Victor Talrose: an appreciation". Journal of Mass Spectrometry. 33 (6): 499–501. Bibcode:1998JMSp...33..499N. doi:10.1002/(SICI)1096-9888(199806)33:6<499::AID-JMS684>3.0.CO;2-C. ISSN 1076-5174.