Diphosphene is inert to ground-state oxygen but can be oxidized by triplet oxygen to give a mixture of phosphine oxides and hydroxy benzophosphole oxide. Compared to oxygen involved oxidation, reaction of diphosphene with ozone is much more rapid and indicates a 2:1 (ozone:diphosphene) stoichiometry. Ozonolysis of bis[tris(trimethylsilyl)methyl]diphosphene (TsiP) gives a cyclic diperoxides.