arenium ions 

https://doi.org/10.1351/goldbook.A00436
Cations derived formally by the addition of a hydron or other cationic species to any position of an arene, e.g. C6H7+, benzenium. The term includes:
  1. Arenium σ-adducts (Wheland intermediates) (which are considered to be intermediates in electrophilic aromatic substitution reactions) and other cyclohexadienyl cations.
  2. Arenium π-adducts, such as:
[σ-adduct (sigma-adduct), π-adduct (pi-adduct)].
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1318 [Terms] [Paper]
See also:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1077 [Terms] [Paper]
Citation: 'arenium ions' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.A00436 RIS BibTex EndNote
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Last revised: October 7, 2008