Carbocations are positively charged species that contain a carbon atom with only three bonds instead of the usual four. This results in an electron deficiency, making them highly reactive intermediates in organic chemistry. They often form during reactions such as alkyl halide elimination or nucleophilic substitution. The stability of a carbocation depends on its structure. Tertiary carbocations, which have three alkyl groups attached to the positively charged carbon, are more stable than secondary or primary carbocations. This stability is due to the electron-donating effects of the surrounding alkyl groups, which help to stabilize the positive charge.