Illustrated Glossary of Organic Chemistry

Carbocation: A contraction of carbon cation. A structure with a positive formal charge on carbon due to an open octet. Formerly called carbonium ion, but this term is considered outdated.

Carbocations can be categorized by the number of carbons directly bonded to the open octet carbon:

	Methyl carbocation No +C-C bonds
	Ethyl carbocation A primary (1o) carbocation One +C-C bond
	Isopropyl carbocation Secondary (2o) carbocation Two +C-C bonds
	Tert-butyl carbocation A tertiary (3o) carbocation Three +C-C bonds