A carbenium ion, also called a carbocation, is a reactive intermediate in which a carbon atom carries a positive charge and an empty p orbital. It is formed when a bonding electron pair leaves heterolytically, taking both electrons with it. Carbenium ions matter because they are key intermediates in many organic reactions, such as the SN1 and E1 mechanisms. Their stability follows the order tertiary > secondary > primary, which governs how readily such reactions proceed.

碳正离子(也称碳阳离子)是一种活性中间体,其碳原子带正电荷并具有一个空 p 轨道。它由一对成键电子异裂离去、带走全部电子而生成。碳正离子之所以重要,是因为它们是许多有机反应(如 SN1 和 E1 机理)的关键中间体。其稳定性遵循叔 > 仲 > 伯的顺序,从而决定这类反应进行的难易。