In chemistry, heterolysis or heterolytic fission (from Greek ἕτερος, heteros, "different," and λύσις, lusis, "loosening") involves cleavage of a chemical bond in a process where both of the electrons involved in the original bond remain with only one of the fragment species. During heterolytic bond cleavage in a neutral molecule, a cation and an anion will be generated. Typically, the more electronegative fragment will retain the pair of electrons.