Bismuth is a radioactive element, but its atoms are relatively stable and last for millions of years. This element has been known for centuries. Thus, the Incas of South America added it to weapons made of bronze alloy to harden them, while the ancient Egyptians used a bismuth mineral to make their cosmetics shine. However, until the mid-18th century it was confused with lead, tin and zinc. As a chemical element, bismuth was officially discovered in 1753 by the scientist Claude Geoffroy. The origin of the name comes from the German words weisse masse" meaning white mass.

Pure bismuth forms an oxide in air that looks like colored crystals called hopper crystals. This element is very brittle and has few uses when not in compound form. Yellow bismuth pigments are used in paints and cosmetics, while various bismuth compounds are also used in medicines. An alloy of bismuth and tin is an ingredient in fire extinguishers.

Summary of properties (Bi)

Atomic weight208.98040(1)
Discoverer (year)Agricola, Georgius (~ 1400)
Natural formmetallic solid (rhombohedral)
Electron configuration[Xe] 414 5d10 6s2 6p3
Melting point (ºC)271
Boiling point (ºC)1560
Abundance in earth's crust (ppm)0.009
Isotope (abundance)209Bi (100)
Density g/cm39.75
Van der Waals radius (pm)207
Covalent radius (pm)150
Electronegativity (Pauling)2.02
Vaporization enthalpy (kJ/mol)151.00
Enthalpy of fusion (kJ/mol)11.30
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.12
Thermal conductivity (W/cm·K) at 25ºC and 1 atm0.080
Oxidation state+5, +3
Electron affinity (eV)0.94
1st Ionization potential (eV)7.2855

Back to the Periodic Table of the Elements.