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. Sodium hydroxide is a multi-million-ton per annum commodity chemical. A hydroxide attached to a strongly electropositive center may itself ionize, liberating a hydrogen cation (H), making the parent compound an acid.
Hydroxide
The mineral malachite is a typical example of a basic carbonate. The formula, CuCO(OH) shows that it is halfway between copper carbonate and copper hydroxide. Indeed, in the past the formula was written as CuCO·Cu(OH). The crystal structure is made up of copper, carbonate and hydroxide ions. The mineral atacamite is an example of a basic chloride. It has the formula, CuCl(OH). In this case the composition is nearer to that of the hydroxide than that of the chloride CuCl·3Cu(OH). Copper forms hydroxyphosphate (libethenite), arsenate (olivenite), sulfate (brochantite), and nitrate compounds. White lead is a basic lead carbonate, (PbCO)·Pb(OH), which has been used as a white pigment because of its opaque quality, though its use is now restricted because it can be a source for lead poisoning.