Lead

Lead is a chemical element with the symbol Pb and atomic number 82. It is a dense, soft, malleable post‑transition metal in group 14. At room temperature it appears bluish‑gray and tarnishes readily. It has a relatively low melting point for a metal (327.5°C) and a density of 11.34 g/cm3. The most common oxidation state is +2; lead(IV) compounds are less stable.

Lead occurs mainly as the mineral galena (lead sulfide, PbS). It is mined, refined, and cast into ingots or alloys. In nature it is often accompanied by silver, zinc, or other metals. Production involves roasting and reduction to yield metallic lead.

Uses include lead‑acid batteries, which account for the largest share of demand. Other important applications are shielding against radiation, ballast and weights, solder and certain alloys, and glass or ceramic glazes. In the past, tetraethyl lead added to gasoline and lead pigments were common; both have been phased out or restricted because of toxicity.

Health and environment: Lead is highly toxic, particularly to the developing nervous system. Exposure can occur via inhalation of dust or fumes or ingestion of contaminated food, water, or traditional remedies. Chronic exposure causes cognitive and behavioral effects, anemia, and organ damage. Regulations have reduced emissions and phased out many uses, but contaminated sites and legacy risks remain.

Isotopes and dating: Lead has four stable isotopes—204Pb, 206Pb, 207Pb, and 208Pb—and several radiogenic isotopes. Ratios among 206Pb, 207Pb, 208Pb, and 204Pb are used in lead–lead dating to determine ages of rocks, meteorites, and archaeological materials.