Definition of carbonium ion in English:

carbonium ion


  • An organic cation in which the positive charge is located on a carbon atom.

    • ‘The presence of a water molecule will provide the opportunity for the carbonium ion, and the left side of the ring, to become stable.’
    • ‘Geometry optimisation using density function theory at the pBP / DN - level shows the carbonium ion to be trigonal bipyramidal.’
    • ‘If a carbonium ion is involved in lysozyme catalysis then the TS structure will involve a planar, sp-hybridized C - 1.’
    • ‘This paper reviews the concept of carbonium ions, their formation, stability and reactions.’
    • ‘The key step in a unimolecular reaction is the formation of the carbon cation, or carbonium ion, by the departure of the leaving group.’


Early 20th century: carbonium from carbo- ‘carbon’, on the pattern of ammonium.


carbonium ion

/kɑːˈbəʊnɪəm ˌʌɪən/