Chemical element · reference page

83Bi

Bismuth

Bismuth is element 83 (Bi), located in period 6, group 15 and the p block. At room temperature its reference phase is solid. Its electron configuration is [Xe] 4f14 5d10 6s2 6p3.

Atomic number83

Standard atomic weight208.98040(1)

Group15

Period6

Blockp

Electron configuration[Xe] 4f14 5d10 6s2 6p3

Electronic structure

What controls its chemistry

Group 15 atoms have five valence electrons. They can form three covalent bonds, participate in multiple bonding, or adopt several oxidation states depending on the element and its bonding partners.

The configuration [Xe] 4f14 5d10 6s2 6p3 places bismuth in this family, but the chemistry changes markedly from non-metallic nitrogen and phosphorus to the heavier, more metallic members.

Chemical forms

Compounds, ions and materials

Common families include hydrides, oxides, oxoacids or oxoanions, halides and compounds with metals. Oxidation states from −3 to positive values occur across the group, with the accessible range changing strongly from nitrogen to bismuth.

Physical behaviour

State and phase changes

The reference phase at room temperature is solid. The listed density is 9.78 g/cm³. The melting point is 544.6 K (271.4 °C). The boiling point is 1 837 K (1 564 °C). Pressure, purity and crystal structure can shift measured physical properties.

Occurrence and applications

Where bismuth is found and used

In practice, bismuth is encountered in medical applications, cosmetics and alloys.

In practice

Examples of real uses

Medical applications

Bismuth is used in selected medicines, implants, diagnostics or treatment technologies; the chemical or isotopic form is crucial.

Cosmetics

Certain bismuth compounds are used in pigments, powders or formulations after safety and purity requirements are met.

Alloys

Bismuth is added to metals to change strength, corrosion resistance, melting behaviour or high-temperature performance.

Periodic position

What its neighbours tell us

Bismuth is in period 6 and group 15. In the neighbourhood shown here, it lies between lead and polonium in the same period; antimony is above it and moscovium below it in the same group. These positions make it possible to compare atomic size, ionisation energy and bonding behaviour with nearby elements.

Reference data

Physical and atomic properties

Classificationpost-transition metal

Phase at room temperatureSolid

Electron shells2 · 8 · 18 · 32 · 18 · 5

Density9.78 g/cm³

Melting point544.6 K (271.4 °C)

Boiling point1 837 K (1 564 °C)

Pauling electronegativity2.02

First ionisation energy703 kJ/mol

Electron affinity90.92 kJ/mol

Values describe the element or neutral atom where applicable. Physical data can depend on allotrope, pressure and measurement conditions.

History

Discovery and identification

The discovery of bismuth is associated with Claude François Geoffroy. Recognition of the element, isolation of a pure sample and assignment of its modern atomic number did not necessarily occur at the same time.

Isotopes and atomic weight

How isotope composition changes the numbers

The standard atomic weight is 208.98040(1). This value refers to the isotopic composition of natural terrestrial material, not to the mass of one specific atom.

Bismuth has no stable isotope. Its isotopes are radioactive, and their half-lives and decay modes become important whenever the element is measured, handled or used.

Safety

Handling and exposure

The hazards associated with bismuth depend on chemical form, dose and route of exposure. Pure bismuth, its ions and its compounds can have very different biological and environmental effects, so safety data should be checked for the actual substance being handled.