Lead(II) hydroxide

Lead(II) hydroxide is an inorganic compound with the formula Pb(OH)₂. The material has not been isolated but its existence has been inferred as an ill-defined component of solutions of Pb(II).^[3] "Lead does not appear to form a simple hydroxide, Pb(OH)₂," however.^[4] Instead it forms oxides and oxy-hydroxides.

Lead(II) hydroxide

Names
IUPAC name Lead(II) hydroxide
Other names Lead hydroxide Plumbous hydroxide
Identifiers
CAS Number	19783-14-3 Y
3D model (JSmol)	Interactive image
ChemSpider	8035300 Y
ECHA InfoCard	100.039.358
EC Number	243-310-3
PubChem CID	9859601
CompTox Dashboard (EPA)	DTXSID601015737 DTXSID10431967, DTXSID601015737
InChI InChI=1S/2H2O.Pb/h2*1H2;/q;;+2/p-2 Y Key: VNZYIVBHUDKWEO-UHFFFAOYSA-L Y InChI=1/2H2O.Pb/h2*1H2;/q;;+2/p-2 Key: VNZYIVBHUDKWEO-NUQVWONBAE
SMILES [OH-].[OH-].[Pb+2]
Properties
Chemical formula	Pb(OH)2
Molar mass	241.2 g·mol−1
Solubility in water	0.0155 g/(100 mL) (20 °C)[1]
Solubility product (Ksp)	10−19.85 to 10−14.9[2]
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H332, H351, H360, H373, H410
NFPA 704 (fire diamond)	2 0 0
Related compounds
Other cations	Germanium(II) hydroxide Tin(II) hydroxide Mercury(II) hydroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Preparation

Addition of hydroxide 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.^[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 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.^[5] 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·xH₂O.^[7][8] 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.^[9] 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.^[3]