Cadmium
Cadmium is a soft metal often obtained alongside zinc; it and many of its compounds are toxic.
Cadmium has useful industrial properties, but its toxicity limits applications.
Explore Cadmium's atom- Atomic number
- 48
- Standard atomic weight
- 112.414(4)
- Family
- Transition metal
- Period
- 5
- Group
- 12
- Standard state
- Solid
In everyday life
Some older rechargeable batteries use nickel-cadmium chemistry.
Something to remember
Cadmium use has been restricted in many applications because of health and environmental concerns.
Meet its electrons
[Kr] 5s2 4d10
Published neutral-atom ground-state configuration; excited atoms and ions can differ.
Electrons per shell: 2 · 8 · 18 · 18 · 2.
The playground shows an illustrative shell model. Real electrons are described by quantum orbitals, rather than tiny planets traveling along fixed paths.
A connection to explore
Cadmium and tellurium form cadmium telluride, used in some solar cells.
Meet Tellurium (Te)Properties and conditions
- Standard atomic weight
- 112.414(4)CIAAW 2024 standard atomic weight (dimensionless). Parentheses give uncertainty in the last quoted digits. Source flags: g.CIAAW standard atomic weights ↗ · Retrieved 2026-10-15
- Standard state
- SolidPubChem classification, including explicit predictions where stated. Reference temperature and pressure are not supplied in the table.PubChem periodic table ↗ · Retrieved 2026-10-15
- First ionisation energy
- 8.994 eVEnergy to remove the first electron from an isolated neutral gas-phase atom. Uncertainty is not supplied.PubChem periodic table ↗ · Retrieved 2026-10-15
- Electronegativity
- 1.69 Pauling scaleA dimensionless relative measure; values depend on the chosen scale. Uncertainty is not supplied.PubChem periodic table ↗ · Retrieved 2026-10-15
- Melting point
- 594.22 KPubChem reported value. Pressure, allotrope and measurement uncertainty are not specified in the table; consult the cited source.PubChem periodic table ↗ · Retrieved 2026-10-15
- Boiling point
- 1040 KPubChem reported value. Pressure and measurement uncertainty are not specified in the table; consult the cited source.PubChem periodic table ↗ · Retrieved 2026-10-15
- Density
- 8.69 g/cm³PubChem reported value. Temperature, pressure, allotrope and measurement uncertainty are not specified in the table; gas densities are especially condition-dependent.PubChem periodic table ↗ · Retrieved 2026-10-15
- Oxidation states
- +2Selected PubChem oxidation states; formal electron bookkeeping, not a list of stable free-ion charges or every possible compound.PubChem periodic table ↗ · Retrieved 2026-10-15
- Discovery
- 1817PubChem discovery attribution. Ancient knowledge and competing priority claims cannot always be represented by a single year.PubChem periodic table ↗ · Retrieved 2026-10-15
- Atomic radius
- 158 pmPubChem tabulated radius. Radius definitions depend on bonding and convention; measurement definition and uncertainty are not supplied in this table.PubChem periodic table ↗ · Retrieved 2026-10-15
- Electron affinity
- Not reportedPubChem reported gas-phase electron affinity. Sign conventions and electronic states matter; uncertainty is not supplied in this table.PubChem periodic table ↗ · Retrieved 2026-10-15
Isotopes, abundance and decay
Isotopes share a proton count but have different neutron counts. This selection includes naturally tabulated compositions and a reference isotope for other elements. It is not a list of every known isotope.
Explore 8 isotopes of Cd
| Isotope | Relative atomic mass | Natural fraction | Half-life | Decay |
|---|---|---|---|---|
| Cd-106 | 105.9064599(12) | 0.0125(6) | No decay observed | ;2β+ ? |
| Cd-108 | 107.9041834(12) | 0.0089(3) | No decay observed | ;2β+ ? |
| Cd-110 | 109.90300661(61) | 0.1249(18) | No decay observed | No decay tabulated |
| Cd-111 | 110.90418287(61) | 0.1280(12) | No decay observed | No decay tabulated |
| Cd-112 | 111.90276287(60) | 0.2413(21) | No decay observed | No decay tabulated |
| Cd-113 | 112.90440813(45) | 0.1222(12) | 8.04 Py (uncertainty 0.05) | ;β−=100 |
| Cd-114 | 113.90336509(43) | 0.2873(42) | No decay observed | ;2β− ? |
| Cd-116 | 115.90476315(17) | 0.0749(18) | 26.9 Ey (uncertainty 0.9) | ;2β−=100 |
Fractions use NIST’s terrestrial isotopic compositions, which can vary by sample. Parentheses denote uncertainty in the last digits. Half-lives and decay branches use NUBASE2020; # marks estimates, >/< mark limits. “No decay observed” follows that evaluation and does not prove permanent stability. Decay branch intensities are percentages; SF means spontaneous fission, EC electron capture, IT an isomeric transition.
Follow the science
Use these original references to explore the data and context. Atomic weights can vary with isotope composition; values for elements without stable isotopes may describe a representative isotope rather than a standard atomic weight.