Preparation and structure:
PbO is prepared by heating lead metal in air at 600 C. Alternatively, it is obtained by the thermal decomposition of lead(II) nitrate or lead carbonate:
- 2Pb(NO3)2) → 2PbO + 4NO2 + O2
- PbCO3 → PbO + CO2
The structure of the solid, determined by X-ray crystallography, reveals a pyramidal four-coordinate Pb center. The pyramidal nature indicates the presence of a stereo chemically active lone pair of electrons.
The red and yellow forms of this material are related by a small change in enthalpy:
PbO(red) → PbO(yellow) ΔH = 1.6 kJ/mol
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 + H2O + OH– → [Pb(OH)3]–
–Synthetic lead(II) oxide prepared by heating lead or certain lead compounds in air poisonous yellow or reddish-yellow solid, used in making lead glass, pottery glazes, and rubber
The red and yellow forms of this material are related by a small change in enthalpy: PbO(red) → PbO(yellow) ΔH = 1.6 kJ/mol
Applications of Lead Oxide:
1)Lead oxide is widely used in manufacturing of glass. It increases the refractive index of glass, decreases viscosity of glass, increases electrical resistivity of glass. It is used in preparing ceramic glazes.
2)A mixture with glycerine sets to a hard, waterproof cement that has been used to join the flat glass sides and bottoms of aquaria. A mixture of PbO with glycerine sets to a hard, water proof cement that is used to join the flat glass sides and bottoms of aquariums.
3)It is a component of lead paints. In powdered tetragonal litharge form, it can be mixed with linseed oil and then boiled to create a weather-resistant sizing used in gilding.
4)The litharge would give the sizing a dark red color that made the gold leaf appear warm and lustrous, while the linseed oil would impart adhesion and a flat durable binding surface.
5)PbO is used in certain condensation reactions in organic synthesis.
6)PbO is the main ingredient of the paste used for filling the plates during manufacturing of lead-acid batteries.
7)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.
