Carbocation

A carbocation is a positively-charged carbon ion. It has only six electrons in its outer valence shell instead of the eight valence electrons that most atoms want. Therefore the carbon cation is unstable and very reactive, seeking to fill its octet of valence electrons as well as regain its neutral charge.

In organic chemistry, the carbocation is often the target of nucleophilic attack by nucleophiles like OH^- ions or halogen ions.