The chemical symbol for lead, Pb, comes from the Latin word plumbum. In ancient Roman times, water pipes used in plumbing were made of this soft metal. Lead compounds are found in the minerals crocoite, anglesite and galena. The latter, the main source of pure lead. Lead was much more commonly used in the past as an important ingredient in paints, hair dyes and insecticides. A common historical use was in glassware. However, it has limited applications today, due to its toxicity. Since lead absorbs radiation well, it is used as a shielding agent. It is also used as ballast for diving and in automobile batteries.

Summary of properties (Pb)

Atomic weight207.2(1)
Discoverer (year)unknown (ancient times)
Natural formmetallic solid (face centered cubic)
Electron configuration[Xe] 414 5d10 6s2 6p2
Melting point (ºC)327
Boiling point (ºC)1740
Abundance in earth's crust (ppm)14
Isotope (abundance)204Pb (1.4), 206Pb (24.1), 207Pb (22.1), 208Pb (52.4)
Density g/cm311.35
Van der Waals radius (pm)202
Covalent radius (pm)145
Electronegativity (Pauling)2.33
Vaporization enthalpy (kJ/mol)179.50
Enthalpy of fusion (kJ/mol)4.77
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.13
Thermal conductivity (W/cm·K) at 25ºC and 1 atm0.350
Oxidation state+4, +2
Electron affinity (eV)0.36
1st Ionization potential (eV)7.4167

Back to the Periodic Table of the Elements.