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(Redirected from Lead oxide)
'Lead(II) oxide', is the chemical compound with the formula PbO Also known as litharge, this compound exists in both rhombic and yellow (orthorhombic) forms, which are red and yellow, respectively. The yellow form is known as massicot.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
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:
:Pb(NO3)2) → PbO + NO2 + 1/2 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 stereochemically active lone pair of electrons.[1]
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]-
PbO is a component of paints and in glass, as well as in vulcanization of rubber. A mixture with glycerine sets to a hard, waterproof cement that has been used to join the flat glass sides and bottoms of aquaria. PbO is used in certain condensation reactions in organic synthesis.[2]
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.
1. Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
2. “1,4-Diphenylbutadiene” Corson, B. B. Organic Syntheses, Coll. Vol. 2, p.229 (1943). http://www.orgsyn.org/orgsyn/pdfs/CV2P0229.pdf.
★ Case Studies in Environmental Medicine - Lead Toxicity
★ ToxFAQs™: Lead
★ National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
★ [1]
'Lead(II) oxide', is the chemical compound with the formula PbO Also known as litharge, this compound exists in both rhombic and yellow (orthorhombic) forms, which are red and yellow, respectively. The yellow form is known as massicot.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
| Contents |
| Preparation and structure |
| Reactions |
| Applications |
| References |
| External links |
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:
:Pb(NO3)2) → PbO + NO2 + 1/2 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 stereochemically active lone pair of electrons.[1]
Reactions
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]-
Applications
PbO is a component of paints and in glass, as well as in vulcanization of rubber. A mixture with glycerine sets to a hard, waterproof cement that has been used to join the flat glass sides and bottoms of aquaria. PbO is used in certain condensation reactions in organic synthesis.[2]
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.
References
1. Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
2. “1,4-Diphenylbutadiene” Corson, B. B. Organic Syntheses, Coll. Vol. 2, p.229 (1943). http://www.orgsyn.org/orgsyn/pdfs/CV2P0229.pdf.
External links
★ Case Studies in Environmental Medicine - Lead Toxicity
★ ToxFAQs™: Lead
★ National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
★ [1]
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