|Atomic mass||208.9806 amu|
Bismuth is a hard, brittle metal, discovered in 1450.
It occurs as the free element as well as the oxide, Bi2O3, called bismuth ocher, and as the sulfide, Bi2S3, called bismuth glance. Bismuth also occurs in lead ores, therefore, its principal commercial source is from the by-product of refining lead.
Like antimony, bismuth expands when it solidifies. So, where sharp, well-defined edges of castings are important (i.e. in type metals), bismuth and antimony are used as alloying agents.
The melting point of bismuth is 271°C, but form alloys that melt as low as 47°C.
Bismuth alloys have wide applications in automatic sprinkler systems, electrical fuses, and safety plugs in boilers where low-melting alloys are essential.
Bismuth is also used as medicine. The active ingredient in Pepto-Bismol is Bismuth Subsalicylate.
In recent scientific research, bismuth-containing compounds are reported to be promising candidates for high temperature superconducting materials.