» This article is about the hydroxyl functional group. For the Hydroxyl radical see Hydroxyl radical. Hydroxyl in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond. The neutral form is a hydroxyl radical and the hydroxyl anion is called a hydroxide. When the oxygen atom is linked to a larger molecule the hydroxyl group is a functional group (HO¯ or ¯OH) . Hydroxyl group The term hydroxyl group is used to describe the func… (More on Hydroxyl)