Lead(II) hydroxide

Lead(II) hydroxide
Names
IUPAC name
Lead(II) hydroxide
Other names
lead hydroxide
plumbous hydroxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.039.358
Properties
Pb(OH)2
Molar mass 241.21 g/mol
Appearance white amorphous powder
Density 7.41 g/cm3 [2]
Melting point 135 °C (275 °F; 408 K) (decomposes)
0.0155 g/100 mL (20 °C)[3]
1.42 x 10−20
Solubility soluble in dilute acid and alkalis;
insoluble in acetone and acetic acid
Hazards
T
R-phrases (outdated) R25
S-phrases (outdated) (S1/2) S20/21 S29/56 S45
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
0
2
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Lead(II) hydroxide, Pb(OH)2, is a hydroxide of lead, with lead in oxidation state +2. It is doubtful that such a simple compound exists.[4] Lead basic carbonate (PbCO3·2Pb(OH)2) or lead(II) oxide (PbO) is encountered in practice where lead hydroxide is expected. This has been a subject of considerable confusion in the past.

Preparation

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 = Pb6O4(OH)4.[5] 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.[6]

Reactions

In 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, forms Pb(OH)+, Pb(OH)2(aqueous), Pb(OH)3−, and other species, including several polynuclear species, e.g., Pb4(OH)44+, Pb3(OH)42+, Pb6O(OH)64+.[5]

Lead hydrate

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.[7][8]

References

  1. ↑ http://www.commonchemistry.org/ChemicalDetail.aspx?ref=1319-46-6&terms=lead(II)+hydroxide
  2. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  3. ↑ Handbook of Chemistry and Physics, 1st edition, 2000, CRC Press ISBN 0-8493-0740-6
  4. ↑ G. Todd and E. Parry (1964). "Character of Lead Hydroxide and Basic Lead Carbonate". Nature. 202 (4930): 386–387. doi:10.1038/202386a0.
  5. 1 2 Von Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, "Inorganic Chemistry", Academic Press, 2001 (Google books).
  6. ↑ R. A. Howie; W. Moser (1968). "Structure of Tin(II) "Hydroxide" and Lead(II) "Hydroxide". Nature. 219: 372–373. doi:10.1038/219372a0.
  7. ↑ http://www.google.com/patents/US527830
  8. ↑ http://www.google.com/patents/US496109
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