Bismuth (Bi)


  • Symbol: Bi
  • Atomic Number: 83
  • Atomic Weight: 208.98040
  • Element Classification: Post-transition Metal
  • Discovered By: Known to alchemists since at least the 15th century
  • Discovery Date: Recognized as a distinct element by Claude François Geoffroy in 1753
  • Name Origin: German: ‘Weisse Masse’ meaning white mass; later changed to ‘Bismuth’ by Kaspar Neumann
  • Density(g/cc): 9.78
  • Melting Point: 271.5°C
  • Boiling Point: 1564°C
  • Appearance: Silver-white with a pink tinge, brittle metal with a crystalline structure
  • Atomic Radius(pm): 156


Bismuth was known to alchemists since at least the 15th century and was often confused with tin and lead. Its distinct properties as a separate element were recognized by Claude François Geoffroy in 1753. The name “bismuth” comes from the German ‘Weisse Masse’, meaning white mass, which was later adapted to bismuth by Kaspar Neumann. It is known for its low toxicity among heavy metals and unique physical properties.

Relation to Other Elements

Bismuth is a post-transition metal in group 15 of the periodic table, sharing the group with nitrogen, phosphorus, arsenic, and antimony. Bismuth is unique among metals for having one of the lowest values of thermal conductivity and a high resistance to oxidation at room temperature. Unlike most other metals, bismuth expands upon freezing. It predominantly forms trivalent (Bi3+) compounds and is characterized by its relatively low melting point and high boiling point.

Natural Occurrence

Bismuth occurs naturally in its elemental form and in minerals such as bismuthinite (Bi2S3) and bismite (Bi2O3). However, it is often produced as a byproduct of refining lead, copper, tin, silver, and gold ores. The largest bismuth reserves are found in China, which is also the largest producer of bismuth.


Bismuth has several applications, benefiting from its unique properties and low toxicity:

  • Pharmaceuticals: Bismuth compounds, such as bismuth subsalicylate (Pepto-Bismol), are used in medications to treat upset stomach, indigestion, and diarrhea.
  • Alloys: Bismuth is used in alloys with low melting points, including solders, fusible plugs, and fire detection devices. Its expansion upon solidification makes it useful in casting of printing type.
  • Cosmetics and Pigments: Bismuth oxychloride is used in cosmetics as a pigment due to its pearlescent properties.
  • Metallurgy: Bismuth is added to steel and aluminum alloys to improve machinability. It is also used in the manufacture of free-machining steels for precision machining properties.
  • Electronics: Bismuth telluride is used in thermoelectric materials for cooling systems in computers and other electronic devices.

The discovery and utilization of bismuth have highlighted the element’s versatility across various industries, from pharmaceuticals and cosmetics to metallurgy and electronics. Its unique physical and chemical properties, coupled with its low toxicity, make bismuth a valuable resource in modern technology and medicine.


Lead (Pb)

Polonium (Po)