Electrofuge

In chemistry, an electrofuge is a leaving group which does not retain the lone pair of electrons from its previous bond with another species (in contrast to a nucleofuge, which does). It can result from the heterolytic breaking of covalent bonds. After this reaction an electrofuge may possess either a positive or a neutral charge; this is governed by the nature of the specific reaction.

An example would be the loss of H⁺ from a molecule of benzene during nitration.

The word 'electrofuge' is commonly found in older literature, but its use in contemporary organic chemistry is now uncommon.