A carbanion is a negatively charged ion that contains a carbon atom with an extra pair of electrons. This extra electron pair gives the carbon a negative charge, making it a reactive species in chemical reactions. Carbanions are important in organic chemistry, as they can act as nucleophiles, meaning they can donate electrons to form new bonds with positively charged species. Carbanions can be formed through various methods, such as deprotonation of hydrocarbons or by the reaction of alkyl halides with strong bases. Their stability depends on the surrounding atoms and groups, with more stable carbanions often being found in resonance-stabilized structures or those adjacent to electronegative atoms.