Lead(II) hydroxide

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Lead(II) hydroxide
Hydroxid olovnatý.PNG
Identifiers
CAS number [1] 1319-46-6[1] N
ChemSpider 8035300 YesY
Jmol-3D images Image 1
Properties
Molecular formula 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)
Solubility in water 1.55 g/100 mL (20 °C)
Solubility product, Ksp 1.42 x 10−20
Solubility soluble in dilute acid and alkalis;
insoluble in acetone and acetic acid
Hazards
EU classification Toxic (T)
R-phrases R25
S-phrases (S1/2) S20/21 S29/56 S45
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Lead(II) hydroxide, Pb(OH)2, is a hydroxide of lead, with lead in oxidation state +2. Although it appears a fundamentally simple compound, it is doubtful if lead hydroxide is stable as a solid phase.[3] 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[edit]

When an alkali hydroxide is added to a solution of a lead(II) salt, then 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.[4]

Reactions[edit]

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+.[4]

Lead hydrate[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.[5] [6]

References[edit]

  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. ^ G. Todd and E. Parry (1964). "Character of Lead Hydroxide and Basic Lead Carbonate". Nature 202 (4930): 386–387. doi:10.1038/202386a0. 
  4. ^ a b Von Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, "Inorganic Chemistry", Academic Press, 2001 (Google books).
  5. ^ http://www.google.com/patents/US527830
  6. ^ http://www.google.com/patents/US496109

External links[edit]