Magnesium oxide (MgO), or magnesia, is a white hygroscopic solid mineral that occurs by itself as periclase and is a antecedent of magnesium (see aswell oxide). It has an empiric blueprint of MgO and consists of a filigree of Mg2+ ions and O2− ions captivated calm by ionic bonding. Magnesium hydroxide forms in the attendance of baptize (MgO + H2O → Mg(OH)2), but it can be antipodal by heating it to abstracted moisture.

Magnesium oxide was historically accepted as magnesia alba (literally, the white mineral from magnesia – added sources accord magnesia alba as MgCO3), to differentiate it from magnesia negra, a atramentous mineral absolute what is now accepted as manganese.

While “magnesium oxide” commonly refers to MgO, magnesium achromatize MgO2 is aswell accepted as a compound. According to evolutionary clear anatomy prediction,[5] MgO2 is thermodynamically abiding at pressures aloft 116 GPa (gigapascals), and a absolutely new semiconducting suboxide Mg3O2 is thermodynamically abiding aloft 500 GPa. Because of its stability, MgO is acclimated as a archetypal arrangement for investigating vibrational backdrop of crystals.