Chemistry:Lead(II) hydroxide
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| Names | |
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| IUPAC name
Lead(II) hydroxide
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Other names
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| Identifiers | |
3D model (JSmol)
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PubChem CID
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| Properties | |
| Pb(OH) 2 | |
| Molar mass | 241.2 g·mol−1 |
| Appearance | White amorphous powder |
| Density | 7.41 g/cm3[1] |
| Melting point | 135 °C (275 °F; 408 K) (decomposes) |
| 0.0155 g/(100 mL) (20 °C)[2] | |
Solubility product (Ksp)
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1.42 x 10−20 |
| Solubility | Soluble in dilute aqueous solutions of acids and alkalis; readily soluble in acetone, nitric acid and acetic acid |
| Hazards | |
| GHS pictograms |   
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| GHS Signal word | Danger |
| H302, H332, H351, H360, H373, H410 | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other cations
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
 verify (what is   ?)
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| Infobox references | |
Lead(II) hydroxide, Pb(OH)
2, is a hydroxide of lead, with lead in oxidation state +2.
Preparation
When a hydroxide is added to a solution of a lead(II) salt, a hydrated lead oxide PbO · xH
2O (with x < 1) is obtained. Careful hydrolysis of lead(II) acetate solution yields a crystalline product with a formula 6PbO · 2H2O or Pb
6O
4(OH)
4.[3] This material is a cluster compound, consisting of an octahedron of Pb centers, each face of which is capped by an oxide or a hydroxide. The structure is reminiscent of the Mo
6S
8 subunit of the Chevrel phases.[4]
Reactions
In aqueous solution, lead(II) hydroxide is a somewhat weak base, forming lead(II) ion, Pb2+, under weakly acidic conditions. This cation hydrolyzes and, under progressively increasing alkaline conditions, it becomes somewhat weak acid, and it forms Pb(OH)+
, Pb(OH)
2(aqueous), Pb(OH)−
3, and other species, including several polynuclear species, e.g., Pb
4(OH)4+
4, Pb
3(OH)2+
4, Pb
6O(OH)4+
6.[3]
Upon heating to decomposition temperatures, it forms lead oxide (PbO) in the yellow form, litharge.
History
The name lead hydrate has sometimes been used in the past but it is unclear whether this refers to Pb(OH)
2 or PbO · xH
2O.[5][6] In 1964 it was believed that such a simple compound did not exist, as lead basic carbonate (2PbCO
3 · Pb(OH)
2) or lead(II) oxide (PbO) was encountered where lead hydroxide was expected.[7] This has been a subject of considerable confusion in the past. However, subsequent research has demonstrated that lead(II) hydroxide does indeed exist as one of a series of lead hydroxides.[8]
References
- ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN:0-07-049439-8
- ↑ Handbook of Chemistry and Physics, 1st edition, 2000, CRC Press ISBN:0-8493-0740-6
- ↑ 3.0 3.1 Von Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, "Inorganic Chemistry", Academic Press, 2001 (Google books).
- ↑ R. A. Howie; W. Moser (1968). "Structure of Tin(II) "Hydroxide" and Lead(II) "Hydroxide". Nature 219 (5152): 372–373. doi:10.1038/219372a0. Bibcode: 1968Natur.219..372H.
- ↑ "Process of treating lead hydrate produced by electrolysis". https://www.google.com/patents/US527830.
- ↑ "Process of manufacturing white lead". https://www.google.com/patents/US496109.
- ↑ G. Todd and E. Parry (1964). "Character of Lead Hydroxide and Basic Lead Carbonate". Nature 202 (4930): 386–387. doi:10.1038/202386a0. Bibcode: 1964Natur.202..386T.
- ↑ W. Nimal Perera, Glenn Hefter, and Pal M. Sipos (2001). "An Investigation of the Lead(II)−Hydroxide System". Inorganic Chemistry 40 (16): 3974–3978. doi:10.1021/ic001415o. PMID 11466056.
External links
- Case Studies in Environmental Medicine - Lead Toxicity
- ToxFAQs: Lead
- National Pollutant Inventory - Lead and Lead Compounds Fact Sheet
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