Hydroxide

Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, and a catalyst. The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions.

Chemical properties[edit]

Hydroxide is a compound of an oxygen and hydrogen atom. It is a base, meaning it can accept protons (H+). Hydroxide can also act as a ligand, binding to a central atom in a molecule to form a complex. As a nucleophile, hydroxide can donate an electron pair to an electrophile. In addition, hydroxide can act as a catalyst, speeding up a chemical reaction without being consumed in the process.

Salts of hydroxide[edit]

Salts of hydroxide, known as alkalis, are formed when a metal donates an electron to the hydroxide ion. Some of these salts can dissociate in water, releasing solvated hydroxide ions. This process is known as hydrolysis.

Role in water[edit]

In water, hydroxide is a minor constituent, but it plays an important role in the pH of the water. The concentration of hydroxide ions in water is equal to 10−pH, so the pH of water can be calculated from the concentration of hydroxide ions.

Hydroxide

Chemical properties[edit]

Salts of hydroxide[edit]

Role in water[edit]

See also[edit]