Lead dioxide

Lead(IV) oxide, commonly called lead dioxide or plumbic oxide or anhydrous plumbic acid is a chemical compound with the formula PbO₂. It is an oxide where lead is in an oxidation state +4. It is of an intermediate bond type, displaying both ionic (e.g. the lattice structure) and covalent (e.g. its low melting point and insolubility in water) properties. It is an odorless dark-brown crystalline powder which is nearly insoluble in water. It exists in two crystalline forms. The alpha phase has orthorhombic symmetry; it has been first synthesized in 1941 and identified in nature as a rare mineral scrutinyite in 1988. The more common, tetragonal beta phase was first identified as the mineral plattnerite around 1845 and later produced synthetically. Lead dioxide is a strong oxidizing agent which is used in the manufacture of matches, pyrotechnics, dyes and other chemicals. It also has several important applications in electrochemistry, in particular in the positive plates of lead acid batteries.