Carbanion
An organic ion in which a carbon atom bears a negative charge and a lone pair.
Formula / equation
R₃C⁻
Unit
Dimensionless
In depth
Carbanions are pyramidal and strongly basic and nucleophilic. Their stability increases with the s character of the orbital holding the lone pair and with adjacent electron-withdrawing groups, which is why terminal alkynes and beta-dicarbonyl compounds are unusually acidic.
Examples in the real world
The acetylide ion; enolate ions in aldol reactions; the carbon nucleophile of a Grignard reagent.