https://doi.org/10.1351/goldbook.C00812
A generic name for @C00817@, real or hypothetical, that have at least one important @C01309@ containing a tervalent carbon atom with a vacant p-orbital. (The name implies a protonated carbene or a substitution derivative thereof.) The term was proposed (and rejected) as a replacement for the traditional usage of the name @C00839@. To avoid ambiguity, the name should not be used as the root for the systematic nomenclature of carbocations. The corresponding difficulty confused @C00839@ nomenclature for many years. For example, the term 'ethylcarbonium ion' has at times been used to refer either to CH3CH2+ (ethyl @C00907@) or (correctly) to CH3CH2CH2+ (propyl @C00907@).
Sources:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1092 [Terms] [Paper]
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1324 [Terms] [Paper]
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1092 [Terms] [Paper]
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1324 [Terms] [Paper]