Bismuth

Typical wastewaters

• drinking water plumbing (bismuth copper lead free brass)
  Bi(III) dissolved from the alloy surface like lead, then hydrolysed to hydroxo complexes and BiOCl where chloride is present
  contamination arises after treatment, so there is no source water treatment for it; not detected below 0.005 µg/L in 172 Australian samples
• lead, tungsten and zinc smelting and refining
  Bi(III), hydrolysed to oxide and oxychloride solids at neutral pH, in smelter and refinery effluents where bismuth is a by-product

1 · Identity

Symbol, number

Bi, 83

Oxidation states in water

+3 in all natural water chemistry, as hydroxo and chloro complexes and as the solids BiOCl and Bi₂O₃; +5 only in the strong oxidant sodium bismuthate, which is a laboratory reagent, not a water species.

Note

The element chapter covers the metal, the lead substitute market, pigments and pharmaceuticals. This chapter is about Bi(III) hydrolysis and where the element appears in water.

2 · Occurrence in water

Natural sources

Weathering of bismuthinite and of the sulfide ores of lead, tungsten, tin and copper that carry it (element chapter); the hydrolysed ion partitions to particles at once, so dissolved bismuth in natural water is very low. In an Australian survey bismuth was not detected (below 0.005 µg/L) in 172 drinking water samples (NHMRC).

Anthropogenic sources

Bismuth copper alloys replacing lead in plumbing brass are the source NHMRC identifies for drinking water; bismuth subsalicylate and other bismuth medicines reach sewage after excretion; smelter and refinery effluents where bismuth is a by-product; cosmetics and pigment plants using bismuth oxychloride and vanadate (element chapter). No effluent concentration was read.

3 · Speciation

Bi³⁺ hydrolyses strongly at any natural pH to hydroxo complexes and, with chloride, to bismuth oxychloride; the trihalides and nitrate hydrolyse in water to the oxyhalides and oxynitrate (element chapter). Knight and Turner found linear sediment sorption isotherms up to 2000 µg/L with distribution coefficients that fell from 106,000 L/kg at pH 5.0 to 17,700 L/kg at pH 9.0 in river water, consistent with hydroxo complexes sorbing to the surface, and an order of magnitude higher sorption in seawater at pH 8.0 (1,530,000 L/kg) that they attribute to organic complexation and colloids; bismuth also binds to colloidal organic matter that flocculates on estuarine mixing, so catchment bismuth is retained in estuaries.

Solubility

Bi₂O₃, BiOCl and Bi₂S₃ are insoluble; the nitrate and chloride dissolve only in acid and hydrolyse on dilution (element chapter).

Hydrolysis

Strong; the trihalides hydrolyse to BiOX in water (element chapter). No hydrolysis constants were read.

Complexation

Chloride in acid; organic and colloidal binding in estuaries (Knight and Turner 2020).

Precipitates

BiOCl, Bi(OH)₃ and Bi₂O₃ in neutral water; Bi₂S₃ under sulfide.

4 · Role in treatment

5 · Removal and control

6 · Analytics

Sampling pitfalls

Bismuth hydrolyses and sorbs to bottle walls within minutes at neutral pH; acidify at collection and filter first if dissolved bismuth is wanted. Do not store in chloride free acid and expect the same answer as in chloride bearing samples.

7 · Regulatory limits

Limits change, and many are set locally. Treat these as the published values to start from, not as your compliance target: check the standard in force at your site and the numbers written into your own permit.

8 · Health and environmental effects

Toxicity

Very low: bismuth is swallowed as a stomach medicine (element chapter); NHMRC reports nephrotoxicity and mortality in animals at high doses and human neurotoxicity and kidney damage from medication overdose, with bioavailability strongly dependent on the chemical form.

Bioaccumulation

Both duckweed and the amphipod Echinogammarus veneris accumulated bismuth strongly from bismuth nitrate solutions (Iannilli 2025).

Ecotoxicity

Species specific: Lemna minor showed no effect on growth or photosynthesis over 7 days at 0 to 242 mg/L bismuth nitrate, whereas the amphipod showed DNA damage in the comet assay even at the lowest concentration tested in 24 hours (Iannilli 2025); no water quality criterion exists.

Identity

Name and symbol

Bismuth, Bi

Atomic number

83 protons

Position

group 15 · period 6 · p-block · post-transition metal

CAS number

7440-69-9

Atomic structure

Atomic mass

208.98 u

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p³
[Xe] 6s²⁴f¹⁴⁵d¹⁰⁶p³

Electrons per shell

2, 8, 18, 32, 18, 5

Valence electrons

5 outer shell

Physical properties

State at room temperature

Solid

Melting point

544.55 K (271.4 °C)

Boiling point

1,837 K (1,563.85 °C)

Density

9.807 g/cm3

Appearance

lustrous brownish silver

Thermal conductivity

7.97 W/(m·K)

Electrical resistivity

1.29 µΩ·m at 20 °C

Electrical conductivity

775,193.798 S/m

Crystal structure

rhombohedral

Molar heat capacity

25.52 J/(mol·K)

Chemical properties

Oxidation states

+5, +3

Electronegativity

2.02 (Pauling Scale)

Ionisation energy

7.289 eV
1st 703, 2nd 1,610, 3rd 2,466 kJ/mol

Electron affinity

0.946 eV

Atomic radius

empirical 148, covalent 148, van der Waals 207 pm

Ionic radius

Bi³⁺ 103; Bi⁵⁺ 76 pm

Reactivity

The heaviest pnictogen and the least toxic of the heavy metals, chemically like arsenic and antimony but more metallic; +3 is its state in almost all compounds, and the bulk metal is stable in dry and moist air, attacked only by oxidising acids, hot steam and the halogens.

with water

Stable in moist air and cold water; red-hot bismuth reacts with steam to the oxide and hydrogen: $\ce{2 Bi + 3 H2O -> Bi2O3 + 3 H2}$, the only water reaction.

with oxygen, air

Stable in air at ordinary temperatures (a thin oxide gives the metal its pink or iridescent cast); on heating it burns with a blue flame to the trioxide: $\ce{4 Bi + 3 O2 -> 2 Bi2O3}$, the yellow trioxide.

with acids

Dissolves in concentrated sulfuric acid: $\ce{2 Bi + 6 H2SO4 -> Bi2(SO4)3 + 3 SO2 + 6 H2O}$, and in nitric acid: $\ce{Bi + 6 HNO3 -> Bi(NO3)3 + 3 NO2 + 3 H2O}$, but in hydrochloric acid only when oxygen is present.

with halogens

Reacts with all the halogens to the trihalides: $\ce{2 Bi + 3 Cl2 -> 2 BiCl3}$, fluorine at 500 C giving the only pentahalide BiF5; the trihalides hydrolyse in water to the oxyhalides BiOX.

Typical compounds

• Bi₂O₃ bismuth(III) oxide
  yellow pigment, solid oxide electrolyte, from burning the metal
• Bi₂S₃ bismuth(III) sulfide
  bismuthinite, the chief ore
• BiCl₃ bismuth(III) chloride
  hydrolyses in water to bismuth oxychloride
• BiOCl bismuth oxychloride
  pearlescent pigment, bismuth white, in cosmetics
• Bi(NO₃)₃ bismuth(III) nitrate
  from nitric acid, hydrolyses to the oxynitrate
• NaBiO₃ sodium bismuthate
  strong Bi(V) oxidant, oxidises manganese to permanganate

Occurrence, production and use

Crustal abundance

8.5×10-3 milligrams per kilogram

Oceanic abundance

2×10-5 milligrams per liter

Occurrence and sources

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.

• by-product of lead ore processing; of tungsten and other ores (China, Vietnam); of zinc (Japan, Korea)
  China (leading producer), Laos, Korea, Japan, Kazakhstan, Bolivia, Bulgaria
• native bismuth, bismuthinite (Bi2S3), bismite (Bi2O3)
  Tasna, Bolivia (inactive since 1996) and one mine in China are the only primary sources
• crustal and oceanic abundance
  about 0.18 ppm crust ¹; 0.0085 mg/kg crust and 0.00002 mg/L seawater ²

Extraction, production

By-product refining from lead, tungsten, zinc, copper, tin, silver and gold ore processing

no separation chemistry stated by the sources

Recycled bismuth alloy scrap

3 to 10 percent of US apparent consumption in 2020 to 2024

Uses

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.

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.

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.

"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 thermocoupling material, and has found application as a carrier for 235U or 233U fuel in nuclear reactors. Its soluble salts are characterized by forming unsoluble 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.

• Pharmaceuticals and cosmetics
  • bismuth subsalicylate stomach remedies; compounds for burns, intestinal disorders and ulcers
  • basic bismuth carbonate for indigestion
  • bismuth oxychloride pearlescent and oxide yellow pigments in cosmetics
  chemicals for cosmetic, industrial, laboratory and pharmaceutical use are the largest US consumption (usgs-mcs2025-bismuth)
• Chemicals (pigments and glazes): bismuth nitrate, oxychloride and vanadate for ceramic glazes, crystalware, high-performance and pearlescent pigments
• Metallurgy and plumbing
  • lead-free brass for pipe fittings, fixtures and water meters
  • free-machining aluminium and steel, malleable cast iron additive
  • lead-free solders, fishing weights, ammunition
• Fusible alloys and electronics
  • low-melting alloys for fire sprinkler triggers, fuses, fire detectors, lens holding, oil-well plugs, tube bending
  • bismuth telluride thermoelectrics; bismuth-tellurium-oxide film paste for semiconductors
• Mining: bismuth in lead, zinc, tin and tungsten ore processing

Safety, toxicity

GHS classification, signal word Danger

• H370 Causes damage to organs Specific target organ toxicity, single exposure
• H372 Causes damage to organs through prolonged or repeated exposure Specific target organ toxicity, repeated exposure

Discovery and name

Discovered by

Arabic alchemists

Discovered

before AD 1000

First isolated

not in sources

Named by

not in sources

Origin of the name

possibly from German Wismuth, itself perhaps from weiße Masse, "white mass"

It is a white, crystalline, brittle metal with a pinkish tinge. It occurs in a native state. 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).