Bismuth
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³ · 2 · 8 · 18 · 32 · 18 · 5
The heaviest practically stable element and the most diamagnetic metal. Bismuth is officially radioactive, but its half-life is a billion times the age of the universe, so in practice it lasts forever.
3D model
Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.
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Atomic properties
- Atomic number
- 83
- Atomic mass
- 208.98 а.е.м.
- Electron configuration
- [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³
- Electrons per shell
- 2 · 8 · 18 · 32 · 18 · 5
- Block
- p-block
- Group
- Pnictogens
- Period
- 6
- Electronegativity (Pauling)
- 2.02
- Electronegativity (Allen)
- 2.01
- Atomic radius
- 143 pm
- Covalent radius
- 148 pm
- Van der Waals radius
- 207 pm
- Ionisation energy 1
- 703 kJ/mol
- Ionisation energy 2
- 1 610 kJ/mol
- Ionisation energy 3
- 2 466 kJ/mol
- Ionisation energy 4
- 4 370 kJ/mol
- Ionisation energy 5
- 5 400 kJ/mol
- Electron affinity
- 91.2 kJ/mol
- Common oxidation states
- +3
- Oxidation states
- -3, -2, -1, +1, +2, +3, +4, +5
Physical properties
- State at 25 °C
- solid
- Density
- 9.78 g/cm³
- Melting point
- 544.7 K · 271.6 °C
- Boiling point
- 1 837 K · 1 563.9 °C
- Speed of sound
- 1 790 m/s
Thermal properties
- Heat of fusion
- 11.3 kJ/mol
- Heat of vaporisation
- 179 kJ/mol
- Specific heat capacity
- 0.122 J/(g·K)
- Thermal conductivity
- 7.97 W/(m·K)
Mechanical properties
- Young's modulus
- 32 GPa
- Shear modulus
- 12 GPa
- Bulk modulus
- 31 GPa
- Poisson ratio
- 0.33
- Mohs hardness
- 2.25
- Brinell hardness
- 94.2 MPa
Electrical and magnetic properties
- Electrical resistivity
- 1 290 nΩ·m
- Magnetic ordering
- diamagnetic
- Curie point
- no data
- Néel point
- no data
- Superconducting point
- no data
Crystal structure
- Crystal structure
- rhombohedral
- Lattice constants
- a = 474.6 pm · c = 1 186 pm
Abundance
- In the crust
- 0.009 mg/kg
- In the ocean
- 2·10⁻⁵ mg/L
- In the universe
- 0.0007 mg/kg
- In the human body
- no data
Isotopes
| Isotope | Abundance | Half-life | Decay mode |
|---|---|---|---|
| 209Bi | 100 % | 2.009·10¹⁰ Gyr | α |
Bismuth-209 was considered stable until 2003, when French physicists detected its alpha decay with a half-life of 2·10¹⁹ years.
Discovery
- Year of discovery
- 1753
- Discovered by
- Claude François Geoffroy
- Where
- France
- Origin of the name
- from German weisse Masse (white mass)
History
Bismuth was known in the Middle Ages but regularly confused with lead and tin. Claude Geoffroy showed conclusively in 1753 that it is an element in its own right.
Where it occurs
0.009 mg/kg of the crust. It is mined mostly as a by-product of lead, tungsten and copper.
How it is produced
From lead refinery slimes by the Kroll–Betterton process. World output is about 20 000 tonnes a year.
Role in living things
No biological role, but bismuth compounds are used medically against peptic ulcers — they suppress Helicobacter pylori.
Safety
One of the few heavy metals with low toxicity, which is why it is chosen to replace lead. Prolonged high doses do still cause encephalopathy.
Uses
- A lead replacement in solders, plumbing brass and shot — bismuth is non-toxic
- Bismuth subsalicylate in stomach remedies
- Low-melting alloys for fuses and sprinklers
- Cosmetics: bismuth oxychloride gives a pearlescent sheen
- Bismuth telluride in thermoelectric modules
Curiosities
- Bismuth crystals with their iridescent terraces are the most recognisable in mineralogy; the rainbow comes from interference in the oxide film.
- Until 2003 bismuth was thought to be the heaviest stable element; that title now belongs to lead.
- Bismuth expands on freezing, as water and antimony do.
- The pink stomach remedy familiar to Americans is bismuth subsalicylate.