The delocalized carbenium ion, cycloheptatrienylium,
C7H7+, derived formally by detachment of one hydride ion from the
CH2 group of cyclohepta-1,3,5-triene and substitution derivatives thereof.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1373 (https://doi.org/10.1351/pac199567081307)