Hydroxyl in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond (single bond). The neutral form's a hydroxyl radical and the hydroxyl anion's called a hydroxide. When the oxygen atom's linked to a larger molecule the hydroxyl group's a functional group (OH) . Hydroxide (HO¯ or ¯OH anion)'s a polyatomic ion with a charge of negative one. Hydroxide anion's a base and's used to make solutions or compounds basic. Hydroxyl group The… (More on Hydroxyl)