Lead hydroxide (Pb(OH)2) (19783-14-3) Physical and Chemical Properties
Lead hydroxide (Pb(OH)2)
Inorganic lead(II) hydroxide is a white solid used as a precursor in materials synthesis and analytical reference preparations, with procurement and handling governed by strict occupational hygiene considerations.
| CAS Number | 19783-14-3 |
| Family | Inorganic lead compounds |
| Typical Form | Powder or crystalline solid |
| Common Grades | EP, USP |
Lead hydroxide is an inorganic lead(II) hydroxide belonging to the class of heavy-metal hydroxides. Structurally it consists of lead in the +2 oxidation state coordinated to hydroxide ligands; the solid is best described as an ionic, polymeric lattice of \(\ce{Pb^{2+}}\) cations and hydroxide anions that aggregates to a white, poorly soluble solid. Electronically the Pb(II) center presents a stereochemically active lone pair that influences local coordination geometries and can favour formation of layered or polymeric hydroxide/oxide motifs rather than discrete molecular units.
Chemically, \(\ce{Pb(OH)2}\) behaves primarily as a basic inorganic hydroxide: it dissolves in mineral acids to give soluble lead(II) salts and, under strongly basic conditions, exhibits amphoteric behavior forming soluble plumbite/plumbate anions (for example \(\ce{Pb(OH)3^-}\) and \(\ce{Pb(OH)4^2-}\)). The solid is essentially ionic and non-volatile, insoluble in organic solvents, and prone to surface carbonation and dehydration to lead oxides under thermal or aging conditions. In practical terms its poor water solubility, chemical reactivity with acids, sulfides and carbonates, and well‑established systemic toxicity as a lead compound define handling, storage and regulatory constraints.
Common commercial grades reported for this substance include: EP, USP.
Basic Physical Properties
Density
No experimentally established value for this property is available in the current data context.
Melting or Decomposition Point
No experimentally established value for this property is available in the current data context.
Solubility in Water
\(\ce{Pb(OH)2}\) is sparingly soluble in water and typically presents as a fine, white precipitate or suspension. It reacts readily with acids to yield soluble \(\ce{Pb^{2+}}\) salts according to reactions such as \( \ce{Pb(OH)2 + 2 H+ -> Pb^{2+} + 2 H2O} \). In excess strong base it forms soluble plumbite/plumbate species, for example \( \ce{Pb(OH)2 + OH- -> Pb(OH)3^-} \) and further deprotonation to \( \ce{Pb(OH)4^2-} \) under highly alkaline conditions. Insolubility in most organic media and a tendency to form colloidal suspensions are typical for this class of ionic hydroxides.
Solution pH (Qualitative Behavior)
A water suspension of \(\ce{Pb(OH)2}\) is alkaline owing to the presence of hydroxide; the apparent alkalinity will be neutralized by addition of acids. In the presence of excess alkali the system becomes soluble via formation of plumbite/plumbate anions. No quantitative bulk pH value is provided in the current data context.
Chemical Properties
Acid–Base Behavior
\(\ce{Pb(OH)2}\) functions primarily as a Brønsted base (hydroxide donor) and displays limited amphoterism. Protonation with acids produces the \(\ce{Pb^{2+}}\) cation and water, while reaction with concentrated base yields soluble hydroxo‑lead anions as noted above. These acid–base transformations control solubility and speciation in aqueous processing streams and determine the product outcome in synthesis of downstream lead salts.
Reactivity and Stability
Thermally and chemically \(\ce{Pb(OH)2}\) tends to dehydrate to lead oxide phases and to form basic salts on exposure to carbonates, sulfates or sulfides (e.g., conversion to basic carbonates or black lead sulfide upon contact with sulfide). Oxidation of Pb(II) to Pb(IV) is not favoured under mild conditions but can occur under strong oxidising environments to give higher‑valent lead oxides. The solid is generally stable under dry, neutral conditions but will slowly carbonate on exposure to atmospheric CO2 and is reactive toward acids, strong bases and sulfide sources.
Molecular and Ionic Parameters
Formula and Molecular Weight
Molecular formula: \(\ce{H2O2Pb}\)
Molecular weight: 241 \(\mathrm{g}\,\mathrm{mol}^{-1}\)
Exact mass (monoisotopic): 241.98213
Topological polar surface area (computed): 2 Ų (computed descriptor)
Hydrogen-bond donors/acceptors (computed): H‑bond donor count = 2; H‑bond acceptor count = 2
Rotatable bond count (computed): 0
Constituent Ions
The ionic constituents in the solid and in aqueous solution (under prototypical conditions) are \(\ce{Pb^{2+}}\) and \(\ce{OH-}\) (stoichiometry: one \(\ce{Pb^{2+}}\) per two \(\ce{OH-}\)). Under strongly basic conditions soluble hydroxo complexes such as \(\ce{Pb(OH)3^-}\) and \(\ce{Pb(OH)4^2-}\) are formed.
Identifiers and Synonyms
Registry Numbers and Codes
CAS number: 19783-14-3
EC number: 243-310-3
DSSTox Substance ID: DTXSID601015737
Nikkaji Number: J96.326G
Wikidata: Q412573
InChI: InChI=1S/2H2O.Pb/h2*1H2;/q;;+2/p-2
InChIKey: VNZYIVBHUDKWEO-UHFFFAOYSA-L
SMILES: [OH-].[OH-].[Pb+2]
IUPAC name (computed descriptor): lead(2+) dihydroxide
Synonyms and Common Names
Common or deposited synonyms found in the data context include: lead hydroxide; Lead(II) hydroxide; plumbanediol; lead(2+);dihydroxide; Lead hydroxide (Pb(OH)2).
Industrial and Commercial Applications
Functional Roles and Use Sectors
Lead hydroxide is used industrially as an intermediate in the manufacture of other inorganic lead compounds and in processes where controlled lead(II) speciation is required. Its role is primarily that of precursor/inorganic reagent rather than an end‑use consumer product. Commercial activity and industrial manufacture of the substance have been documented in multiple jurisdictions.
Typical Application Examples
Typical, class‑level application examples include: precursor for preparation of lead salts and basic lead compounds; use in laboratory syntheses for producing lead‑containing materials; and applications where insoluble lead hydroxide precipitants are formed for separation or conversion to other lead oxides. Because of toxicity and regulatory restrictions, many historical uses of lead compounds (e.g., pigments, glazing agents) are now controlled or restricted.
Safety and Handling Overview
Health and Environmental Hazards
Lead hydroxide is a lead(II) compound and shares the systemic and environmental toxicity profile associated with inorganic lead. Toxicological endpoints include neurotoxicity (particularly developing nervous systems), nephrotoxicity, hematologic effects (interference with heme biosynthesis), reproductive and developmental toxicity, and carcinogenic potential. The substance is harmful by ingestion and inhalation and poses long‑term organ damage hazards on repeated exposure. It is also highly toxic to aquatic organisms with long-lasting effects.
Reported hazard statements associated with lead compounds in the data context include acute toxicity by ingestion and inhalation, carcinogenicity risk, reproductive toxicity, specific target‑organ toxicity (single and repeated exposure) and aquatic toxicity. Permissible exposure limits cited in occupational guidance are commonly 0.05 \(\mathrm{mg}\,\mathrm{m}^{-3}\) expressed as elemental lead (\( \text{as Pb} \)). Biological monitoring indices described include blood lead reference values on the order of 200 \(\mathrm{\mu g}\,\mathrm{L}^{-1}\) (20 \(\mathrm{\mu g}\)/100 mL) in some guidance schemes. Medical treatment of significant lead poisoning includes chelation therapy with agents such as EDTA, dimercaprol or DMSA under clinical supervision.
For detailed hazard, transport and regulatory information, users should refer to the product‑specific Safety Data Sheet (SDS) and local legislation.
Storage and Handling Considerations
Handling should minimise dust generation and prevent inhalation or ingestion. Engineering controls such as local exhaust ventilation or fume hoods, and the use of appropriate personal protective equipment (gloves, eye protection, respiratory protection when necessary) are recommended. Containers should be kept tightly closed, stored in a cool, dry, well‑ventilated area separated from strong acids and strong oxidisers, and labelled to prevent accidental use. Waste and spill residues must be managed as hazardous lead‑containing materials in accordance with applicable waste regulations. For detailed procedures on decontamination, emergency response and disposal consult the product SDS and applicable regulations.
