Characteristics Crystals Occurrence Applications

Compounds Isotopes Bismuth Data Interactive Periodic Table

Alchemical Symbol

Characteristics

Pure Bismuth is a white, brittle metal with a slight pink color.  Bismuth is usually mixed with other metals, such as Lead, Tin, Iron or Cadmium to form low-melting alloys.  These alloys are used in such things as automatic fire sprinkler systems, fire detection systems and electrical fuses.

It is a brittle metal with a pinkish hue, often occurring in its native form with an iridescent oxide tarnish showing many refractive colors from yellow to blue.  Among the heavy metals, Bismuth is unusual in that its toxcity is much lower than that of its neighbors in the periodic table such as Lead, Thallium, and Antimony.  No other metal is more naturally diamagnetic (as opposed to superdiamagnetic) than Bismuth, and it has a high electrical resistance.   Of any metal, it has the second lowest thermal conductivity and the highest Hall Effect.  When deposited in sufficiently thin layers on a substrate, bismuth is a semicondictor, rather than a poor metal.  When combusted with Oxygen, Bismuth burns with a blue flame ant its oxide forms yellow fumes.

While Bismuth was traditionally regarded as the element with the heaviest stable isotope,  it had long been thought to be unstable on theoretical grounds.  Not until 2003 was this demonstrated when researchers at the Institut d'Astrophysique Spatiale in Orsey, France, measured the Alpha emmission half-life of ²⁰⁹Bi to be 19 x 10¹⁸ years, meaning that Bismuth is very slightly radioactive, with a half-life over a billion times longer than the current estimated age of the universe.  Due to its extraordinarily long half-life, for nearly all applications Bismuth can be treated as if it is stable and non-radioactive.  However, the radioactivity is of academic interest because Bismuth is one of few elements whose radioactivity was suspected, and indeed theoretically predicted, before being detected in the laboratory.

Elemental Bismuth is one of very few substances of which the liquid phase is denser than its solid phase; most substances have the opposite characteristics (i.e., they expand when they melt).  Another well-known example of a substance that expands when it solidifies is water.  Because Bismuth expands on freezing, it was long an important component of low-melting typesetting alloys which needed to expand to fill printing molds.

Crystals

Though virtually unseen in nature, high-purity Bismuth can form into distinctive Hopper Crystals.  These colorful laboratory creations are typically sold to collectors.   Bismuth is relatively nontoxic and has a low melting point.  Crystals can be grown using a household stove, but this carries significant risk of burns and should not generally be attempted without extensive metal-smelting experience.  The resulting crystals will tend to be disappointing when compared to lab-grown crystals.

Occurrence

Bismuth, the heaviest non-radioactive naturally occurring element, was isolated by Basil Valentine in 1450.  It is a hard, brittle metal with an unusually low melting point (271^oC).  Alloys of Bismuth with other low-melting metals such as Tin and Lead have even lower melting points and are used in electrical solders, fuse elements and automatic fire sprinkler heads.

The metal can be found in nature, often combined with Copper or Lead ores, but can also be extracted from Bismuth (III) Oxide by roasting with Carbon.

In the Earth's crust, Bismuth is about twice as abundant as Gold.  It is not usually economical to mine it as a primary product. Rather, it is usually produced as a byproduct of the processing of other metal ores, especially Lead, but also Tungsten or other metal alloys.

The most important ores of Bismuth are Bismuthinite and Bismite.  The People's Republic of China is the world's largest producer of Bismuth, followed by Mexico and Peru.   Canada, Bolivia, and Kasakhstan are smaller producers.

The average price for Bismuth in 2000 was $7.70 per kilogram.  It is relatively cheap, since like lead (but to a much lesser extent), it is radiogenic, being formed from the natural decay of Uranium and Thorium (specifically, by way of Neptunium-237 or Uranium-233).

Applications

Bismuth Oxide (Bi₂O₃), a Bismuth compound, is used as a yellow pigment in paints and cosmetics.   Bismuth Oxychloride (BiOCl) is used to make a pigment known as Bismuth White.   Bismuth Carbonate (Bi₂(CO₃)₃) is used to treat diarrhea and gastric ulcers.

Bismuth Oxychloride is sometimes used in cosmetics.  Also Bismuth Subnitrate and Bismuth Subcarbonate are used in medicine.  Bismuth Subsalicylate (the active ingredient in Pepto-Bismol) is used as an antidiarrheal and to treat some other gastro-intestinal diseases. Also, Bismuth Subgallate (the active ingredient in Devrom) is used as an internal deodorant to treat malodor from flatulence (or gas) and stool.   Other Uses:

• Strong permanent magnets can be made from the alloy Bismanol, BiMn. 
• Many Bismuth alloys have low melting points and are widely used for fire detection and suppression system safety devices.
• Bismuth is used as an alloying agent in production of malleable irons.
• Bismuth is finding use as a catalyst for making acrylic fibers.
• A carrier for U-235 or U-233 fuel in nuclear reactors. 
• Bismuth has also been used in solders.  The fact that Bismuth and many of its alloys expand slightly when they solidify make them ideal for this purpose.
• Bismuth Subnitrate is a component of glazes that produces an iridescent luster finish.
• Bismuth Telluride is an excellent thermoelectric material; it is widely used.
• As a replacement propellant for Xenon in Hall Effect thrusters. 
• In 1997 an antibody conjugate with Bi-213, which has a 45 minute half-life, and decays with the emission of an alpha-particle, was used to treat patients with leukemia.

In the early 1990s, research began to evaluate bismuth as a nontoxic replacement for lead in various applications:

• As noted above, Bismuth has been used in solders; its low toxicity will be especially important for solders to be used in food processing equipment.
• As a pigment in artist's oil paint
• As an ingredient of ceramic glazes 
• As an ingredient in free-machining brass for plumbing applications
• As an ingredient in free-cutting steels for precision machining properties
• As a catalyst for making acrylic fibers
• In low-melting alloys used in fire detection and extinguishing systems
• As an ingredient in lubricating greases 
• As a dense material for fishing sinkers.
• As the Oxide, Carbonate, or Subnitrate in crackling microstars (Dragon's Eggs) in pyrotechnics. 
• As a replacement for Lead in shot and bullets.  The UK, USA and many other countries now prohibit the use of Lead shot for the hunting of wetland birds, as other creatures in the wetlands are prone to Lead Poisoning from ingestion of Lead shot.   Bismuth-Tin alloy shot is one alternative that provides similar ballistic performance to Lead (another less expensive but also poorer-performing alternative is steel shot, although some prefer it for the increased damage it does).

  Bismuth core bullets are also starting to appear for use in indoor shooting ranges, where particles of lead from the bullet impacting the backstop can be a problem.  Due to Bismuth's crystalline nature, the Bismuth bullets shatter into a non-toxic powder on impact, making recovery and recycling easy. The lack of malleability does, however, make Bismuth unsuitable for use in expanding hunting bullets.

Compounds

Isotopes

Once thought to be the heaviest stable isotope to exist in nature, experiments conducted in 2002 showed that Bismuth-209 is unstable and decays into Thallium-205 through alpha decay.  Bismuth-209 has a half-life of roughly   19,000,000,000,000,000,000 years.

(Ger. Weisse Masse, white mass; later Wisuth and Bisemutum) In early times bismuth was confused with tin and lead. Claude Geoffroy the Younger showed it to be distinct from lead in 1753. It is a white crystalline, brittle metal with a pinkish tinge. It occurs native. The most important ores are bismuthinite or bismuth glance and bismite. Peru, Japan, Mexico, Bolivia, and Canada are major bismuth producers. Much of the bismuth produced in the U.S. is obtained as a by-product in refining lead, copper, tin, silver, and gold ores. Bismuth is the most diamagnetic of all metals, and the thermal conductivity is lower than any metal, except mercury. It has a high electrical resistance, and has the highest Hall effect of any metal (i.e., greatest increase in electrical resistance when placed in a magnetic field). "Bismanol" is a permanent magnet of high coercive force, made of MnBi, by the U.S. Naval Surface Weapons Center. Bismuth expands 3.32% on solidification. This property makes bismuth alloys particularly suited to the making of sharp castings of objects subject to damage by high temperatures. With other metals such as tin, cadmium, etc., bismuth forms low-melting alloys which are extensively used for safety devices in fire detection and extinguishing systems. Bismuth is used in producing malleable irons and is finding use as a catalyst for making acrylic fibers. When bismuth is heated in air it burns with a blue flame, forming yellow fumes of the oxide. The metal is also used as a thermocouple material, and has found application as a carrier for U235 or U233 fuel in nuclear reactors. Its soluble salts are characterized by forming insoluble basic salts on the addition of water, a property sometimes used in detection work. Bismuth oxychloride is used extensively in cosmetics. Bismuth subnitrate and subcarbonate are used in medicine.

Source: CRC Handbook of Chemistry and Physics, 1913-1995. David R. Lide, Editor in Chief. Author: C.R. Hammond