Magnesium ozonide is a compound with the formula MgO<sub>3</sub>. Much like other ozonides, it is only stable at low temperatures. Unlike other ozonide compounds, magnesium ozonide is white rather than the typical red colour.
Magnesium ozonide can be made by passing a dilute mixture of ozone in liquid nitrogen and over magnesium at -259 ðC:
Magnesium is also known to form bisozonide complexes, containing Mg(O<sub>3</sub>)<sub>2</sub> complexed with argon or carbon monoxide, in an argon matrix.