Uranium dioxideperoxide, is a useful research compound. Its molecular formula is H2O4U and its molecular weight is 304.042 g/mol. The purity is usually 95%. 

Uranium peroxide is a pale-yellow, soluble peroxide of uranium. It is found to be present at one stage of the enriched uranium fuel cycle and in yellowcake prepared via the in situ leaching and resin ion exchange system. It is confirmed human carcinogen.

The substance is fatal if swallowed, is fatal if inhaled, is toxic to aquatic life with long lasting effects and may cause damage to organs through prolonged or repeated exposure. This is according to the harmonized classification and labelling (ATP01) approved by the European Union.