Lead(II) hydroxide, Pb(OH)₂, is a

hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. ...

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...

, with lead in

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

+2. 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 Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula Pb O. PbO occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern ap ...

(PbO) was encountered where lead hydroxide was expected. 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.

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 Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysi ...

lead(II) acetate Lead(II) acetate (Pb(CH3COO)2), also known as lead acetate, lead diacetate, plumbous acetate, sugar of lead, lead sugar, salt of Saturn, or Goulard's powder, is a white crystalline chemical compound with a slightly sweet taste. Like many other l ...

solution yields a crystalline product with a formula 6PbO·2H₂O = Pb₆O₄(OH)₄.Von Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, "Inorganic Chemistry", Academic Press, 200
(Google books)
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.

Reactions

In solution, lead(II) hydroxide is a somewhat weak base, forming lead(II) ion, Pb²⁺, under weakly

acidic In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a ...

conditions. This

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

hydrolyze Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis i ...

s and, under progressively increasing

alkaline In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a ...

conditions, forms Pb(OH)⁺, Pb(OH)₂(aqueous), Pb(OH)₃⁻, and other

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

, including several polynuclear species, e.g., Pb₄(OH)₄⁴⁺, Pb₃(OH)₄²⁺, Pb₆O(OH)₆⁴⁺.

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.

References

External links

Case Studies in Environmental Medicine - Lead Toxicity

{{Hydroxides Hydroxides Lead(II) compounds