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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| ChemSpider | |
| ECHA InfoCard | 100.039.358 |
| EC Number |
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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 | |
| GHS labelling: | |
  
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| 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).
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Lead(II) hydroxide, Pb(OH)2, is a hydroxide of lead, with lead in oxidation state +2.
Preparation
[edit]When 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
[edit]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., 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
[edit]The 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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