Category: Transition metal
Atomic Number: 48
Period: 5 | Group: 12
Block: d-block
A soft, toxic metal that gave the world rechargeable NiCd cells and the brilliant yellow of old paint.
| Property | Value |
|---|---|
| Phase at STP | Solid |
| Density | N/A |
| Melting Point | 594.22 K (321.07 °C) |
| Boiling Point | 1040.00 K (766.85 °C) |
| Heat Capacity | N/A |
| Property | Value |
|---|---|
| Atomic Mass | 112.4140 u |
| Electronegativity (Pauling) | N/A |
| Oxidation States | -2, +1, +2 |
| Electron Configuration |
| Discovered By | Unknown |
|---|---|
| Discovery Year | 1817 |
| Named After | Latin cadmia, "calamine" |
A puzzle in zinc carbonate (1817)
In 1817 Friedrich Stromeyer, a professor at Göttingen who also inspected pharmacies, investigated samples of zinc carbonate that turned yellow when heated even though they contained no iron. He traced the color to a new metal and named it cadmium, from the Latin cadmia, the old name for zinc carbonate ore (calamine).
An independent discovery
In the same year Karl Samuel Leberecht Hermann found the element independently in zinc oxide from Silesia, and both men are credited with its discovery.
From pigment to pollutant
Cadmium found little use until the late 19th century, when cadmium sulfide became a popular yellow pigment. Its use grew in the 20th century in plating, batteries and plastics, until its toxicity, made clear by itai-itai disease in Japan, led to restrictions from the 1970s onward.
| ISOTOPE | Neutrons | Natural Abundance | Half-life | Decay Mode |
|---|---|---|---|---|
| Cd-106 | 58 | 1.245% | Stable | - |
| Cd-108 | 60 | 0.888% | Stable | - |
| Cd-110 | 62 | 12.470% | Stable | - |
| Cd-111 | 63 | 12.795% | Stable | - |
| Cd-112 | 64 | 24.109% | Stable | - |
| Cd-113 | 65 | 12.227% | 8.04 × 10¹⁵ yrs | β⁻ |
| Cd-114 | 66 | 28.754% | Stable | - |
| Cd-116 | 68 | 7.512% | 3.3 × 10¹⁹ yrs | 2β⁻ |
Data: IAEA Nuclear Data Section, LiveChart of Nuclides, ground-state evaluations, retrieved October 10, 2026. Abundance is the share of atoms in the natural element; a dash means the isotope has no standard natural abundance.
Batteries
Nickel-cadmium (NiCd) rechargeable batteries have long been the largest use of cadmium. They are robust and work well in the cold, and they are still used in aircraft, railway and backup power systems. The European Union has banned them from most portable devices, where lithium-ion and nickel-metal hydride batteries have replaced them.
Solar panels
Cadmium telluride (CdTe) is the leading thin-film solar cell material and is used in large solar farms.
Pigments, coatings and alloys
Pigments: cadmium sulfide and cadmium selenide give bright yellows, oranges and reds for artists' paints, plastics, ceramics and glass.
Coatings: electroplated cadmium protects steel fasteners and connectors in aircraft and military equipment from corrosion.
Alloys: some low-melting and bearing alloys contain cadmium.
Nuclear: cadmium absorbs neutrons and is used in control rods and shielding.
Restrictions
Because of its toxicity, the EU RoHS directive limits cadmium in electrical and electronic equipment to 0.01% by weight, and many countries restrict it in plastics, jewelry and toys.
| Earth's Crust | N/A |
|---|---|
| Universe | N/A |