Lead(II) hydroxide, (Pb(OH)2), is a hydroxide of lead, with lead in oxidation state 2.
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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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| ChemSpider | |
| ECHA InfoCard | 100.039.358 |
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PubChem CID
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CompTox Dashboard (EPA)
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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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10−19.85 to 10−14.9[3] |
| Solubility | Soluble in dilute aqueous solutions of acids and alkalis Insoluble in acetone and acetic acid[1] |
| Hazards | |
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| Danger | |
| H302, H332, H351, H360, H373, H410 | |
| NFPA 704 (fire diamond) | |
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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).
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Preparation
editWhen a hydroxide is added to a solution of a lead(II) salt, a hydrated lead oxide PbO·xH2O (with x < 1) is obtained. Careful hydrolysis of lead(II) acetate solution yields a crystalline product with a formula 6PbO·2H2O or Pb6O4(OH)4.[4] 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 Mo6S8 subunit of the Chevrel phases.[5]
The following formula can also prepare it:
Pb(NO₃)₂ NaOH = NaNO₃ Pb(OH)₂
Reactions
editIn 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., Pb4(OH)4 4, Pb3(OH)2 4, Pb6O(OH)4 6.[4] Upon heating to decomposition temperatures, it forms lead oxide (PbO) in the yellow form, litharge.
History
editThe name lead hydrate has sometimes been used in the past but it is unclear whether this refers to Pb(OH)2 or PbO·xH2O.[6][7] In 1964 it was believed that such a simple compound did not exist, as lead basic carbonate (2PbCO3·Pb(OH)2) or lead(II) oxide (PbO) was encountered where lead hydroxide was expected.[8] 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.[9]
References
edit- ^ a b Patnaik, Pradyot (2002). Handbook of Inorganic Chemicals. New York, NY: McGraw-Hill. p. 471. ISBN 9780070494398.
- ^ Handbook of Chemistry and Physics, 1st edition, 2000, CRC Press ISBN 0-8493-0740-6
- ^ Internal Corrosion of Water Distribution Systems (2nd ed.). American Water Works Association. 1996. p. 178. ISBN 978-1-61300-170-7.
- ^ a b 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. Bibcode:1968Natur.219..372H. doi:10.1038/219372a0. S2CID 45007541.
- ^ "Process of treating lead hydrate produced by electrolysis".
- ^ "Process of manufacturing white lead".
- ^ G. Todd and E. Parry (1964). "Character of Lead Hydroxide and Basic Lead Carbonate". Nature. 202 (4930): 386–387. Bibcode:1964Natur.202..386T. doi:10.1038/202386a0. S2CID 44941178.
- ^ 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.
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