Cadmium (Cd)
Element 48 · Transition metal · atomic mass 112.41 u · group 12, period 5
Electron shells: 2, 8, 18, 18, 2
Cadmium is a soft, toxic metal once common in pigments and plating, now tightly restricted. It survives mainly in specialist batteries and thin-film solar cells.
Cadmium yellow was a favourite of Monet and Van Gogh before its toxicity was understood.
- Atomic number
- 48
- Atomic mass
- 112.41 u
- Electron configuration
- [Kr] 5s² 4d¹⁰
- Group · period · block
- 12 · 5 · d
- Oxidation states
- +2
- Electronegativity
- 1.69 (Pauling)
- Melting point
- 321 °C
- Boiling point
- 767 °C
- Density
- 8.69 g/cm³
- State at 20 °C
- Solid
- Appearance
- Soft, bluish-white metal
- Discovered
- Friedrich Stromeyer, 1817
48 protons, and 48 electrons when neutral
IUPAC standard atomic weight
Zinc group
What Cadmium is used for
- Nickel-cadmium batteries
- Cadmium telluride solar panels
- Corrosion-resistant plating
- Nuclear reactor control rods
Atomic structure of Cadmium
A neutral cadmium atom has 48 protons and 48 electrons. Its most common isotope carries about 64 neutrons, which is where the mass number 112 comes from. Change the neutron count and you have a different isotope of cadmium; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8, 18, 18, 2. In orbital notation that is [Kr] 5s² 4d¹⁰. As a d-block element its valence count is variable, which is why it can form compounds in several oxidation states.
3D electron orbitals
See where Cadmium's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Cadmium sits in the periodic table
The d-block. Multiple stable oxidation states give them coloured compounds, catalytic ability and the strength that makes them the working metals of industry.
Discovery and naming
Cadmium was discovered by Friedrich Stromeyer in 1817. Its name comes from Latin cadmia, "calamine", which is also why its symbol (Cd) does not match its English name.
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Cadmium?
The standard atomic weight of Cadmium is 112.41 u, as published by IUPAC's Commission on Isotopic Abundances and Atomic Weights.
How many protons, neutrons and electrons does Cadmium have?
Cadmium has 48 protons, because the atomic number is the proton count and that is what makes an atom Cadmium at all. A neutral Cadmium atom has the same number of electrons, 48. The neutron count varies by isotope; the most common one has about 64, since 112 − 48 = 64.
What is the electron configuration of Cadmium?
The electron configuration of Cadmium is [Kr] 5s² 4d¹⁰. Its electrons are arranged 2, 8, 18, 18, 2 across 5 shells.
Is Cadmium a metal?
Yes. Cadmium is classified as a transition metal, on the metallic side of the table.
What group and period is Cadmium in?
Cadmium is in group 12 (the zinc group), period 5, in the d-block. The group is its column and the period is its row.
What is the charge of Cadmium?
Cadmium most commonly forms a 2+ ion. Like most transition metals it has several accessible oxidation states, so the charge depends on the compound.
What is the melting point of Cadmium?
Cadmium melts at 321 °C and boils at 767 °C. That puts it in the solids at everyday temperatures.
What is Cadmium used for?
Nickel-cadmium batteries, Cadmium telluride solar panels, Corrosion-resistant plating, Nuclear reactor control rods. Cadmium is a soft, toxic metal once common in pigments and plating, now tightly restricted.
Who discovered Cadmium, and where does its name come from?
Cadmium (Cd) was discovered by Friedrich Stromeyer in 1817. The name comes from Latin cadmia, "calamine".