Hydroxyl Group Definition – Chemistry Term

The hydroxyl group is a functional group consisting of a hydrogen atom covalently bonded to an oxygen atom. The hydroxyl group is denoted by -OH in chemical structures and has a valence charge of -1. The hydroxyl radical is very reactive, so it quickly reacts with other chemical species. Hydroxyl radicals can cause DNA and cell damage.

Hydroxyl Versus Hydroxy

The terms “hydroxyl” and “hydroxy” tend to be used interchangeably, but they don’t technically mean the same thing. The term hydroxyl means the radical OH. The functional group -OH is more properly called a hydroxy group. Further, the [OH-] anion, which is called hydroxide, consists of a hydroxy group.