Bismuth is a post-transition metal and was discovered in 1753. It is a highly useful metal, and is component of various cosmetics, alloys and medications.
Discovery and History
Bismuth has been known to human civilizations since 1400, but due to close resemblance, it was confused with lead and tin. Bismuth is among the earliest ten elements to be discovered and used by humans. It was discovered as a distinct element in 1753 by Claude Geoffroy the Younger. Bismuth form white oxide layer when exposed to air and its name has been derived from the Latin word “bisemutum” that means “white substance” and dates to 1600s .
Bismuth is ubiquitously distributed on the Earth, both in pure and mineral form. The primary source of bismuth is its mineral, bismuthinite, or bismuth sulfide (Bi2S3) . Bismuth is also obtained as a by-product in the refining processes of silver, lead, tin and gold ores. The leading producers of bismuth include Japan, Canada, Mexico, Peru and Bolivia .
Bismuth is a pinkish white metal. It is solid at room temperature and is lustrous and brittle in nature. Bismuth is a highly diamagnetic element. Bismuth develops a layer of oxide on its surface, that shows various colors from blue to yellow and shows iridescent (shine surface that gives different colors when angel of illumination is changes) property. Bismuth has an exceptionally low thermal conductivity. And high resistance to electric field. It has a low melting point, 271.4 C. Liquid bismuth expands like water when exposed to freezing temperature and forms a crystalline structure. Upon combustion, bismuth gives a blue flame. Its boiling point is 2847C. Bismuth is a very dense metal, 9.78 g/cm3. Bismuth is scarcely radioactive and decay to thallium, but it has an extremely long half-life (20 billion billion years). But due to its extremely long half-life, it is considered stable. Bismuth acts as semiconductor when present in extremely thin layers.
Bismuth is a stable element. It does not react with air at standard temperature, but forms bismuth oxide at high temperature. Bismuth form pentavalent and trivalent compounds, and trivalent being more common. It reacts with various acids, such as nitric acid, hydrochloric acid and sulfuric acid. Among halogens, bismuth reacts with fluorine (at 500C) to form bismuth (V) fluoride.
Significance and Uses
- Bismuth is widely used in medication as bismuth subsalicylate (pink bismuth), (Bismol), for curing diarrhea and upset stomach and as bibrocathol to treat eye infections.
- Bismuth (Bismuth oxychloride) is used in cosmetic industry for the manufacturing of nail colors, eyeshadows and lipsticks. It gives the products the required shine and gloss.
- Bismuth is used in the manufacturing of rubber and synthetic fiber.
- Bismuth is used in nuclear reactors.
- Bismuth is widely used as pigments in paints and is non-toxic alternative of cadmium based paints and colors.
- Bismuth has replaced lead in various alloys, due to its low toxicity compared to lead.
Bismuth has a very low toxicity. The low solubility of bismuth salts in water is the primary cause of low toxicity. However, long term exposure to high levels of bismuth can lead to development of bismuth line on the gums. Bioaccumulation of bismuth has also been known and the biological half-life of bismuth has been reported to be less than a week, but it can persist in the kidneys for many years of individuals given medication with bismuth compounds .
Isotopes of Bismuth
There is one natural isotope of bismuth, bismuth-209. It is one of the heaviest isotopes in nature. Bismuth is considered non-radioactive due to its extraordinary long alpha decay half-life . Various artificial isotopes of bismuth have been synthesized. Various isotopes of bismuth are also formed during the radioactive disintegration chains of different metals, such as uranium-233, radium and actinium .
. Anderson, Schuyler C. “2016 USGS Minerals Yearbook: Bismuth” (PDF). United States Geological Survey. Retrieved 1 July 2016.