In chemistry, heterolysis or heterolytic fission (from Greek ἑτερος, heteros, "different," and λυσις, lusis, "loosening") is chemical bond cleavage of a neutral molecule generating a cation and an anion. In this process the two electrons that make up the bond are assigned to the same fragment.
The energy involved in this process is called heterolytic bond dissociation energy. Bond cleavage is also possible by a process called homolysis. In heterolysis additional energy is required to separate the ion pair. An ionising solvent helps reduce this energy.
In biology, heterolysis refers to necrosis induced by hydrolytic enzymes from surrounding (usually inflammatory) cells. Autolysis is necrosis of a cell by its own enzymes.
- IUPAC Compendium of Chemical Terminology, 2nd Edition (1997): http://www.iupac.org/goldbook/H02809.pdf