[1] During heterolytic bond cleavage of a neutral molecule, a cation and an anion will be generated.
Heterolytic fission almost always happens to single bonds; the process usually produces two fragment species.
Arrhenius pioneered development of ionic theory and proposed definitions for acids as molecules that produced hydrogen ions, and bases as molecules that produced hydroxide ions.
One group in Ukraine did an in-depth study on the role of nucleophilic solvation and its effect on the mechanism of bond heterolysis.
For example, a change of reaction medium from hexane to water increases the rate of tert-Butyl chloride (t-BuCl) heterolysis by 14 orders of magnitude.