Name: Bismuth
Symbol: Bi
Atomic Number: 83
Atomic Weight: 208.980380
Family:  Nitrogen Family
CAS RN: 7440-69-9
Description: A reddish white metal, crystalline, brittle, with high

electrical resistance and low thermal conductivity.
State (25C): Solid
Oxidation states: +3, +5

Molar Volume: 21.37 cm3/mole
Valence Electrons: 6p3

Boiling Point:  1837K, 1564C, 2847F
Melting Point:
544.67K, 271.52C, 520.74F
Electrons Energy Level: 2, 8, 18, 32, 18, 5
Isotopes: 32 + 1 Stable
Heat of Vaporization: 104.8 kJ/mol
Heat of Fusion: 11.3 kJ/mol
Density: 9.75 g/cm3 @ 300K
Specific Heat: 0.12 J/gK
Atomic Radius: 1.63
Ionic Radius: 1.03
Electronegativity: 2.02 (Pauling); 1.67 (Allrod Rochow)
Vapor Pressure: 0.000627 Pa @ 271.52C
Bismuth (New Latin bisemutum from German Wismuth, perhaps from weie Masse, "white mass") was confused in early times with Tin and Lead due to its resemblance to those elements.  Basilius Valentinus described some of its uses in 1450.  Bismuth was first shown to be a distinct element in 1753 by Claude Francois Geoffroy the Younger.  Bismuth does occur free in nature and in such minerals as Bismuthinite (Bi2S3) and Bismite (Bi2O3).   The largest deposits of Bismuth are found in Bolivia, although Bismuth is usually obtained as a by-product of mining and refining Lead, Copper, Tin, Silver and Gold.

Artificial Bismuth was commonly used in place of the actual mineral. It was made by hammering Tin into thin plates, and cementing them by a mixture of White Tartar, Saltpeter, and Arsenic, stratified in a crucible over an open fire.

Bismuth was also known to the Incas and used (along with the usual Copper and Tin) in a special Bronze alloy for knives.

This heavy, brittle, white crystalline trivalent poor metal has a pink tinge and chemically resembles Arsenic and Antimony.  Of all the metals, it is the most naturally diamagnetic, and only Mercury has less thermal conductivity.

1s2 2s2p6 3s2p6d10 4s2p6d10f14 5s2p6d10 6s2p3

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Alchemical Symbol


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.

2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10 4f14
5s2 5p6 5d10
6s2 6p3

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.

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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.


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.


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 (271oC).  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).


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:

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


Bismuth Oxide, Bi2O3 Bismuth Oxychloride, BiOCl
Bismuth Carbonate, Bi2(CO3)3 Bismuthinite, Bi2S3
Bismite, Bi2O3 Bismanol, BiMn

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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.

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Isotope Atomic Mass Half-Life
Bi185 184.998 44 us
Bi186 185.996 15 ms
Bi187 186.993 35 ms
Bi188 187.992 0.21 seconds
Bi189 188.99 680 ms
Bi190 189.989 6.3 seconds
Bi191 190.986 12 seconds
Bi192 191.985 37 seconds
Bi193 192.983 67 seconds
Bi194 193.983 95 seconds
Bi195 194.981 183 seconds
Bi196 195.981 308 seconds
Bi197 196.979 9.33 minutes
Bi198 197.979 10.3 minutes
Bi199 198.978 27 minutes
Bi200 199.9781 36.4 minutes
Bi201 200.977 108 minutes
Bi202 201.9777 1.72 hours
Bi203 202.9769 11.76 hours
Bi204 203.9778 11.22 hours
Bi205 204.9774 15.31 days
Bi206 205.9785 6.243 days
Bi207 206.9785 31.55 years
Bi208 207.9797 368000 years
Bi209 208.9804 (Stable) 1.9 X  1019 years
Bi210 209.9841 5.013 days
Bi211 210.9873 2.14 minutes
Bi212 211.9913 60.55 minutes
Bi213 212.9944 45.59 minutes
Bi214 213.9987 19.9 minutes
Bi215 215.002 7.6 minutes
Bi216 216.006 3.6 minutes
Bi217   97 seconds

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Bismuth Data

Atomic Radius (): 1.63
Atomic Volume cm3/mol : 21.3cm3/mol
Covalent Radius: 1.46
Crystal Structure: Rhombohedral
Ionic Radius: 1.03

Chemical Properties

Electrochemical Equivalents: 2.599 g/amp-hr
Electron Work Function: 4.22eV
Electronegativity: 2.02 (Pauling); 1.67 (Allrod Rochow)
Heat of Fusion: 11.3 kJ/mol
Incompatibilities: unknown
First Ionization Potential: 7.289
Second Ionization Potential: 16.687
Third Ionization Potential: 25.559
Valence Electron Potential: 41.9
Ionization Energy (eV): 7.289 eV

Physical Properties

Atomic Mass Average: 208.9804
Boiling Point: 1837K, 1564C, 2847F
Melting Point: 544.67K, 271.52C, 520.74F
Heat of Vaporization: 104.8 kJ/mol
Coefficient of Lineal Thermal Expansion/K-1: 13.4E-6
Electrical Conductivity: 0.00867 106/cm
Thermal Conductivity: 0.0787 W/cmK
Density: 9.75 g/cm3 @ 300K
Enthalpy of Atomization: 207.1 kJ/mole @ 25C
Enthalpy of Fusion: 10.9 kJ/mole
Enthalpy of Vaporization: 151 kJ/mole
Flammability Class: unknown
Molar Volume: 21.37 cm3/mole
Optical Refractive Index: unknown
Relative Gas Density (Air=1): unknown
Specific Heat: 0.12 J/gK
Vapor Pressure: 0.000627 Pa @ 271.52C
Estimated Crustal Abundance: 8.510-3 milligrams per kilogram
Estimated Oceanic Abundance: 210-5 milligrams per liter

(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