Lead(IV) oxide, commonly known as lead dioxide, is the inorganic compound with the formula PbO?. It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms. IUPAC name :Lead(IV) oxide Other names: Plumbic oxide, Plattnerite Properties Chemical formula PbO2 Molar mass 239.1988 g/mol Appearance dark-brown, black powder Density 9.38 g/cm3 Melting point 290 °C (554 °F; 563 K) decomposes Solubility in water insoluble Solubility soluble in acetic acid insoluble in alcohol Refractive index (nD) 2.3 Structure : Crystal structure hexagonal Hazards GHS labelling: Signal word Danger UN Number: UN1872 Hazard Class: 5.1 Packing Group: III Harmonized Tariff Code: 2824.90 Hazard Statements: H360-H373-H272-H302-H332 May damage fertility