Magnesium peroxide (MgO2) is an odorless accomplished crumb peroxide with a white to fair color. It is agnate to calcium peroxide because magnesium peroxide aswell releases oxygen by breaking down at a controlled amount with water. Commercially, magnesium peroxide generally exists as a admixture of magnesium peroxide and magnesium hydroxide.

O2, analogously to N2, has the adeptness to bind either side-on or end-on. The anatomy of MgO2 has been affected as a triangular appearance with the O2 atom bounden side-on to the magnesium. This adjustment is a aftereffect of the Mg+ altruistic allegation to the oxygen and creating a Mg2+O22−. The band amid to O2 and the magnesium atom has an almost break activity of 90 kJ mol−1.

In the solid state, MgO2 has a cubic pyrite-type clear anatomy with 6-coordinate Mg2+ ions and O22− peroxide-groups, according to beginning abstracts and evolutionary clear anatomy prediction, the closing admiration a appearance alteration at the burden of 53 GPa to a tetragonal anatomy with 8-coordinate Mg2+ ions. While at accustomed altitude MgO2 is a metastable admixture (less abiding than MgO+1/2O2), at pressures aloft 116 GPa it is predicted to become thermodynamically abiding in the tetragonal phase. This abstract anticipation has been experimentally accepted via amalgam in a laser-heated design anvil cell.