Heterolysis, or heterolytic cleavage, is a way of breaking a bond in which one fragment takes both of the shared electrons while the other takes none, generating an anion and a cation. The prefix 'hetero-' signals that the electrons are split unevenly. It matters because it produces the ionic intermediates of many reactions, for example a carbenium ion. Heterolysis contrasts with homolysis, in which the bonding pair is shared evenly to give two radicals.

异裂(异裂断键)是一种断键方式,其中一个碎片获得两个共享电子中的全部,另一个碎片一个也不得,从而生成一个阴离子和一个阳离子。前缀“hetero-(异)”表示电子被不均匀地分开。它之所以重要,是因为它产生许多反应的离子型中间体,例如碳正离子。异裂与均裂形成对照,后者把成键电子对均匀分配,生成两个自由基。