Bismuth is a brittle metal often alloyed with other elements for practical use. Some bismuth alloys melt at comparatively low temperatures and have served in fuses and fire-safety devices. Bismuth compounds also produce pigments and pearly effects, connecting thermal behavior with optical appearance.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
Why must a bismuth solder be evaluated as an alloy?
Bismuth-containing solders and other alloys
FOLLOW THIS RELATIONSHIP
Name the complete mixture
A solder joins materials using an alloy composition. Identify bismuth alongside its alloy partners before asking which thermal or mechanical behavior is useful.
Explore the model (optional)
BiFORM → INTERACTION → CONSEQUENCE
Follow the explanation in either direction. These are authored steps, not a physical clock.
Optional: check your understanding
USE THE EXPLANATION
What evidence best evaluates a proposed replacement solder?
Atomic identity, reference properties and structure models
INTERACTIVE 3D83 visible sites
An electron censusDrag to rotate · scroll or pinch to zoom
[Xe] 4f14 5d10 6s2 6p3. Grouping electrons by principal shell connects the neutral-atom configuration to periodic-table patterns.
What this representation means
A three-dimensional counting diagram. Dots are count markers, not measured electron positions; spherical placement and spacing are arbitrary. There are no electron trajectories here. Orbitals describe quantum states.
Bismuth was handled by metalworkers before chemists consistently distinguished it from lead and tin. Early descriptions gradually separated these similar-looking metals, and Claude François Geoffroy established bismuth as a distinct substance in 1753. Its story makes identification more demanding than simply finding a shiny solid: reproducible differences in properties were needed to show that the material deserved a separate place among the elements.
Early 1500s
Recognition develops
Agricola describes bismuth separately from more familiar metals.
1753
Distinct identity established
Claude François Geoffroy distinguishes bismuth from lead and tin.
Bismuth occurs both as native metal and in such as bismuthinite and bismite. Much material is recovered alongside other metals during processing. Its natural forms can be striking, but the stepped, rainbow-colored crystals often displayed in collections are usually grown from a melt rather than mined in that form.
Bismuth is a metal whose common compounds favor the +3 . It expands as it solidifies, an unusual behavior among metals. films can produce surface colors, while the optical behavior of a manufactured bismuth compound can differ substantially from the appearance of the elemental metal itself.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
CITE THIS PAGE
Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
solid
293.15 K, 101.325 kPa
Melting point in K
544.7 K
at standard pressure unless noted
Boiling point in K
1837 K
101.325 kPa
Density in g/cm³
9.78 g/cm³
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
2.02 Pauling
Pauling scale
First ionization energy in kJ/mol
703 kJ/mol
gas-phase neutral atom, ground state
Covalent radius in pm
148 pm
single-bond covalent radius
Common oxidation states
+3
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust in mg/kg
0.0085 mg/kg
upper continental crust, mass fraction
Has stable isotopes
Yesderived
Discovery year in CE
1753 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 6
Bi 2.02 Pauling · Bismuth
Electronegativity across period 6. Exact values.
Cs
0.79
Ba
0.89
La
1.1
Ce
1.12
Pr
1.13
Nd
1.14
Sm
1.17
Eu
1.2
Gd
1.2
Tb
1.1
Dy
1.22
Ho
1.23
Er
1.24
Tm
1.25
Yb
1.1
Lu
1.27
Hf
1.3
Ta
1.5
W
2.36
Re
1.9
Os
2.2
Ir
2.2
Pt
2.28
Au
2.54
Hg
2
Tl
1.62
Pb
2.33
Bi
2.02
Po
2
At
2.2
Electronegativity down group 15
Bi 2.02 Pauling · Bismuth
Electronegativity down group 15. Exact values.
N
3.04
P
2.19
As
2.18
Sb
2.05
Bi
2.02
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
