Lead carbonates are inorganic lead compounds formed by the reaction of lead ions (Pb²⁺) with carbonate ions (CO₃²⁻). They occur naturally as minerals and are also produced industrially as refined chemical products.
The two most important forms are:
Cerussite – Lead(II) Carbonate (PbCO₃)
Basic Lead Carbonate (White Lead) – 2PbCO₃·Pb(OH)₂
These compounds are insoluble in water, reactive with acids, and historically important in pigments, batteries, ceramics, and corrosion science.
Chemical Composition
| Lead(II) Carbonate – Cerussite (PbCO₃) | |
|---|---|
| Lead (Pb) | ~77.5% |
| Carbonate (CO₃) | ~22.5% |
| Molecular Weight | 267.21 g/mol |
| Basic Lead Carbonate (White Lead) | |
|---|---|
| Lead (Pb) | ~83% |
| Carbonate + Hydroxide | Balance |
Physical Properties
| Property | Typical Value |
|---|---|
| Appearance | White crystalline powder |
| Density | 6.3 – 6.6 g/cm³ |
| Thermal Stability | Low (decomposes) |
| Melting Point | Decomposes ~315–400 °C |
| Solubility in Water | Insoluble |
| Solubility in Acids | Soluble |
| Electrical Conductivity | Insulator |
Mechanical Properties (Context)
| Property | Behavior |
|---|---|
| Hardness | Very low |
| Ductility | None |
| Brittleness | High |
| Tensile Strength | Not applicable |
| Particle Strength | Low |
Lead carbonates are brittle chemical solids; mechanical properties are relevant only for powder handling and pigment processing.
Metallurgical & Chemical Behaviour
Cerussite has an orthorhombic crystal structure, while white lead exhibits a complex layered structure. No metallurgical strengthening, heat treatment, or alloying is possible. Behavior is governed entirely by chemical reactivity.
Key Chemical Characteristics
✔ Insoluble in water
✔ Reacts readily with acids
✔ Decomposes under heat
✔ Converts to PbO during calcination
✔ Excellent opacity (pigment property)
❌ Highly toxic
Refining & Processing Properties
Industrial production methods include:
Carbonation of lead oxide or hydroxide
Controlled precipitation from lead salts
Historical Dutch process (white lead)
Thermal calcination converts lead carbonates into lead oxide for glass, ceramic, and battery applications.
Available Commercial Forms
Fine powder • Pigment-grade powder • Mineral crystals (cerussite) • Chemical precursor feedstock • Laboratory reagent grades
Applications of Lead Carbonates
Pigments & Coatings (Historical)
White lead paints and corrosion-resistant primers (now restricted)
Battery Industry
Precursor for lead oxides and plate formation in lead-acid batteries
Glass & Ceramics
Lead crystal glass, ceramic glazes, optical glass
Mining & Geology
Cerussite as lead ore and indicator mineral
Advantages
✔ High lead content for oxide production
✔ Excellent opacity
✔ Chemically reactive intermediate
✔ Non-volatile solid for controlled handling
Health, Safety & Regulations
⚠ EXTREMELY TOXIC
Strict controls required for dust, handling, and disposal.
Regulated under REACH, EPA, OSHA, and WHO.
Prohibited in consumer paints, cosmetics, and food-contact materials.