oxide

Compound of oxygen and another element, frequently produced by burning the element or a compound of it in air or oxygen.

Oxides of metals are normally bases and will react with an acid to produce a salt in which the metal forms the cation (positive ion). Some of them will also react with a strong alkali to produce a salt in which the metal is part of a complex anion (negative ion; see amphoteric). Most oxides of non-metals are acidic (dissolve in water to form an acid). Some oxides display no pronounced acidic or basic properties. Some elements can form different oxides, for example burning carbon can result in carbon monoxide (CO) or carbon dioxide (CO₂).