Lead is a chemical element with the symbol Pb (from the Latin plumbum) 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, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children.

Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the group, lead tends to bond with itself; it can form chains and polyhedral structures.

Since lead is easily extracted from its ores, prehistoric people in the Near East were aware of it. Galena is a principal ore of lead which often bears silver. Interest in silver helped initiate widespread extraction and use of lead in ancient Rome. Lead production declined after the fall of Rome and did not reach comparable levels until the Industrial Revolution. Lead played a crucial role in the development of the printing press, as movable type could be relatively easily cast from lead alloys. In 2014, the annual global production of lead was about ten million tonnes, over half of which was from recycling. Lead's high density, low melting point, ductility and relative inertness to oxidation make it useful. These properties, combined with its relative abundance and low cost, resulted in its extensive use in construction, plumbing, batteries, bullets and shot, weights, solders, pewters, fusible alloys, white paints, leaded gasoline, and radiation shielding.

Lead is a devastating and persistent neurotoxin that accumulates in soft tissues and bones. It damages the nervous system and interferes with the function of biological enzymes, causing neurological disorders ranging from behavioral problems to brain damage, and also affects general health, cardiovascular, and renal systems. Lead's toxicity was first documented by ancient Greek and Roman writers, who noted some of the symptoms of lead poisoning, but became widely recognized in Europe in the late 19th century.

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Atomic properties

Standard atomic weight207.2 ±1.1 [206.14 … 207.94]
Atomic mass207.21 u

Atomic radii

Radius (empirical)175 pm
Radius (calculated)154 pm
Covalent radius146 ±5 pm
Van der Waals radius202 pm

Atomic shell

Electron configurationXe 4f14 5d10 6s2 6p2
Ionization energy(1st) 7.4166799 eV
(2nd) 15.032499 eV
(3rd) 31.9373 eV
(4th) 42.33256 eV
(5th) 68.8 eV
Shell model

Physical properties

Density11.34 g·cm−3 (293.1 K)
Molar volume1.826·10-5 m3·mol−1
Speed of sound1,260 m·s−1 (293.1 K)


Melting point600.6 K
Boiling point2,022 K
Liquid range1,421 K
Transition temperature7.2 K


Melting enthalpy4.77 kJ·mol-1
Enthalpy of vaporization178 kJ·mol-1
Binding energy195 kJ·mol-1

Heat and conductivity

Specific heat capacity131 J·kg−1·K−1
Thermal conductivity35 W·m-1·K-1
Expansion coefficient2.89·10-5 K-1


Mohs hardness1.5
Brinell hardness38.3 NM·m-2

Elastic properties

Young’s modulus16 GPa
Shear modulus5.6 GPa
Bulk modulus46 GPa
Poisson’s ratio0.44

Electrical properties

Electrical conductivity4.76·106 S·m-1
Resistance2.1·10-7 Ωm


Magnetic susceptibility-2.301·10-5 cm3·mol−1 (298 K)

Chemical properties

Oxidation state2, 4
Standard potential-0.1251 V (Pb2+ + 2e- → Pb)


Pauling scale2.33
Sanderson scale2.29
Allred-Rochow scale1.55
Mulliken scale2.41
Nagle scale1.76
Pearson absolute negativity3.9 eV

Other properties

Natural occurrenceprimordial
Crystal structureFace-centered cubic
Goldschmidt Classificationchalcophile
Superconductorwith transition tempperature (solid body, normal pressure)
Price/kg2 USD

Natural abundances

10 ppb ≈ 1·1011 M☉
10 ppb ≈ 1.98·1010 Mt
1,400 ppb ≈ 1.4 g
Earth’s crust
10,000 ppb ≈ 277,000 Mt
0.03 ppb ≈ 41.1 kt
Flowing water
3 ppb ≈ 48 kt
Human body
1,700 ppb ≈ 119 mg