LEAD CARBONATE

Chemical properties

colorless ortho-rhomb crystal(s); made by adding CO2 to a cold dilute solution of lead acetate; many uses such as a catalyst for organic reactions, in high temp greases, as a photoconductor in electrophotography [KIR78]

Chemical properties

Lead carbonate forms colorless orthorhombic crystals; it decomposes at about 315 °C. It is nearly insoluble in cold water (0.00011 g/100 mL at 20 °C), but is transformed in hot water to the basic carbonate, 2PbCO3·Pb(OH)2. Lead carbonate is soluble in acids and alkalies, but insoluble in alcohol and ammonia.

The Uses of LEAD CARBONATE

Lead carbonate has a wide range of applications. It catalyzes the polymerization of formaldehyde to high molecular weight crystalline poly(oxymethylene) products. It is used in poly(vinyl chloride) friction liners for pulleys on drive cables of hoisting engines. To improve the bond of polychloroprene to metals in wire-reinforced hoses, 10–25 parts of lead carbonate are used in the elastomer. Lead carbonate is used as a component of high pressure lubricating greases; as a catalyst in the curing of moldable thermosetting silicone resins; as a coating on vinyl chloride polymers to improve their dielectric properties; as a component of corrosion-resistant, dispersion-strengthened grids in lead–acid storage batteries; as a photoconductor for electrophotography; as a coating on heatsensitive sheets for thermographic copying; as a component of a lubricantstabilizer for poly(vinyl chloride); as a component in the manufacture of thermistors, and as a component in slip-preventing waxes for steel cables to provide higher wear resistance.

The Uses of LEAD CARBONATE

Lead carbonate (PbCO3) is found in nature as cerussite. It can also be produced in the laboratory by reacting sodium carbonate with chlorine. It is a crystalline poison that was, and to a lesser extent still is, used as a pigment in white house paints.

The Uses of LEAD CARBONATE

Preparation of lead standard solutions

Definition

A naturally occurring form of lead(II) carbonate that is an important lead ore. It forms orthorhombic crystals and is often found together with galena (PbS).

Definition

cerussite: An ore of lead consistingof lead carbonate, PbCO₃. It is usuallyof secondary origin, formed by theweathering of galena. Pure cerussiteis white but the mineral may be grey due to the presence of impurities. Itforms well-shaped orthorhombiccrystals. It occurs in the USA, Spain,and SW Africa.

Production Methods

Lead carbonate is prepared by passing CO2 into a cold dilute solution of lead acetate, or by shaking a suspension of a lead salt less soluble than the carbonate with ammonium carbonate at a low temperature to avoid formation of basic lead carbonate.