Cadmium
Definition and meaning of Cadmium in chemistry.
Cadmium is a soft, highly malleable, bluish-white metal identified by the chemical symbol Cd and an atomic number of 48. It is a significantly toxic element that chemically resembles zinc and is mostly obtained as an industrial byproduct of zinc ore refining. Discovered simultaneously in 1817 by German chemists, it has been primarily utilized in battery manufacturing and electroplating.
In more detail
Located in group 12 of the periodic table, cadmium is a heavy transition metal characterized by a relatively low melting point and a very high resistance to chemical corrosion. It almost always exhibits a stable oxidation state of +2 in its compounds, distinguishing it from many other transition metals that typically display multiple variable valences. Cadmium is found in nature as a minor, naturally occurring component of most zinc ores, particularly the mineral sphalerite, and it extremely rarely occurs in a pure elemental form. Both the pure metal and its chemical compounds are severely toxic and pose immense environmental and biological health risks, leading to strict global regulations regarding their industrial application. Despite its inherent toxicity, the metal provides excellent, sacrificial protection against corrosion when plated onto steel, especially in highly alkaline environments and demanding marine conditions. Additionally, cadmium readily alloys with other metals to create low-melting-point materials used in specialized soldering and brazing applications.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Cd |
| Atomic number | 48 |
| Atomic mass | 112.41 u |
| Category | Transition Metal |
| State at room temperature | Solid |
| Melting point | 321.07 °C |
| Boiling point | 767 °C |
| Year discovered | 1817 |
Cadmium has historically been a key structural component in rechargeable nickel-cadmium (NiCd) batteries, though its widespread use is rapidly declining due to severe environmental toxicity concerns.
Frequently asked questions
Why is cadmium use heavily regulated?
Cadmium and its numerous compounds are highly toxic and carcinogenic, leading to severe health effects upon gradual accumulation in the human body.
Where does commercially available cadmium come from?
It is not typically mined directly; instead, it is primarily extracted as a secondary byproduct during the mining, smelting, and refining processes of zinc ores.