ElementsWhat is cadmium?
Cadmium is a soft, bluish-white metal. It and its compounds are poisonous, so many of its uses have been cut back.
What is cadmium used for?
Rechargeable nickel-cadmium batteries, some solar cells, and yellow, orange and red pigments.
Where the name comes from
From cadmia, the Latin name for a zinc ore in which it was found.
Key facts
- Symbol
- Cd
- Atomic number
- 48
- Atomic mass
- 112.41 u
- Family
- Transition metal
- Period
- 5
- Group
- 12
- Block
- d
- State at room temperature
- Solid
- Melting point
- 321.1 °C (594.22 K, 610 °F)
- Boiling point
- 766.9 °C (1,040 K, 1,412 °F)
- Density
- 8.69 g/cm³
- Electrons per shell
- 2, 8, 18, 18, 2
- Electron configuration
- [Kr]5s2 4d10
- Common oxidation states
- +2
- Electronegativity (Pauling)
- 1.69
- First ionisation energy
- 8.994 eV
- Electron affinity
- no value
- Atomic radius (van der Waals)
- 158 pm
- Discovered
- 1817
Place in the periodic table
Cadmium is element number 48. It sits in period 5 (row 5) of the periodic table, in group 12 (column 12), and belongs to the d-block. Just before it comes silver (47), and just after it comes indium (49). In the same column, zinc is above it and mercury is below it. Elements in one column tend to behave alike.
Family: Transition metals.
Physical properties
At room temperature cadmium is a solid. It melts at 321.1 °C and boils at 766.9 °C, so it stays liquid over a range of 446 degrees. Its density is 8.69 grams per cubic centimetre, so a one-litre block would weigh about 8.69 kilograms. By density it ranks 36th among the 96 elements with a measured value.
Inside the atom
An atom of cadmium has 48 protons in its nucleus and, when neutral, 48 electrons around it. The electrons are arranged in 5 shells: 2, 8, 18, 18, 2. The outermost shell holds 2 electrons. Written in full, the electron configuration is [Kr]5s2 4d10.
Its electronegativity on the Pauling scale is 1.69. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 8.994 electronvolts (about 868 kilojoules per mole). One mole of cadmium weighs 112.41 grams, so a single gram contains about 5.36 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains cadmium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.