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- Author: chemiguru
Lead(II) oxide is the inorganic compound with the formula PbO. Lead(II) oxide occurs in two polymorphs, red, having a tetragonal crystal structure and yellow, having an orthorhombic crystal structure. Both forms occur naturally as rare minerals: the red form is known as litharge and the yellow form is known as massicot.
:PbO2 –(293 °C)→ Pb12O19 –(351 °C)→ Pb12O17 –(375 °C)→ Pb3O4 –(605 °C)→ PbO
Thermal decomposition of lead(II) nitrate or lead carbonate also results in the PbO formation: :2 Pb(NO3)2 → 2 PbO + 4 NO2 + O2 :PbCO3 → PbO + CO2
As determined by X-ray crystallography, the compound features pyramidal four-coordinate Pb center. The pyramidal nature indicates the presence of a stereo-chemically active lone pair of electrons.
PbO is amphoteric, which means that it reacts with both acids and with bases. With acids, it forms salts of Pb2+ via the intermediacy of oxo clusters such as [Pb6O(OH)6]4+. With strong base, PbO dissolves to form plumbite(II) salts:
PbO is used extensively in manufacturing of lead glasses and ceramic glazes as well as in fine dinnerware. For such applications, the PbO is converted in situ to lead silicate, which is less toxic. Other less dominating applications include the vulcanization of rubber and the production of certain pigments and paints. PbO is used in cathode ray tube glass to block X-ray emission, but mainly in the neck and funnel because it can cause discoloration when used in the faceplate. Strontium oxide is preferred for the faceplate.
PbO is used in certain condensation reactions in organic synthesis.
Category:Lead compounds Category:Oxides Category:Common oxide glass components
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