Lead Oxides
Lead Oxides
the chemical compounds of lead and oxygen: Pb2O, PbO, PbO2, Pb3O4, and Pb2O3. Lead oxide (PbO), peroxide (PbO2), and red oxide, also called minium (Pb3O4), are of commercial value. The oxide PbO has the two crystal forms yellow red tetragonal α (massicot) and yellow orthorhombic β (litharge), with a transition point of 587°C. Both forms are poorly soluble in water (0.11 and 0.05 g per liter at 25°C) and have a melting point of 836°C. PbO is amphoteric, with predominantly basic properties. It is obtained through the oxidation of melted Pb with atmospheric oxygen, as well as through the thermal dissociation of lead hydroxide, carbonate, or nitrate. When heated in air (up to 400°–500°C), PbO converts to Pb3O4, an oxide with red tetragonal crystals. PbO2, which has brown tetragonal crystals, is obtained upon interaction of red oxide and nitric acid. Lead peroxide is a strong oxidizing agent; when triturated with powdery sulfur or red phosphorus, it ignites even at room temperature.
PbO is used in the manufacture of lead glass and glazes; PbO2 serves as an oxidizing agent in the chemical industry and in the manufacture of lead batteries; and Pb3O4 is used in the preparation of paints that protect metals from corrosion.