Nickel

Nickel is a chemical element with the symbol Ni and atomic number 28. It is a silvery-white, hard metal in the transition metals, ferromagnetic at room temperature. It has a high melting point of 1,455°C and a density of about 8.90 g/cm3. A protective oxide film gives it corrosion resistance in many environments.

Nickel occurs in the Earth's crust at low abundance and is primarily obtained from sulfide and laterite ores. The main ore minerals include pentlandite and garnierite. Commercial production involves mining, smelting to produce a matte, and refining by electrolysis or other processes to yield pure nickel. Hydrometallurgical routes are also used for some ores. Major producers include Canada, Russia, Australia, Indonesia and the Philippines.

Uses: The largest portion of nickel is used to make stainless steel and other corrosion-resistant alloys. It is also employed in nickel-copper alloys such as cupronickel, specialized nickel alloys (Monel, Inconel), electroplating, and coinage. Nickel is used in batteries for rechargeable devices and some hybrid vehicles, and in certain catalysts.

Chemistry and alloys: Nickel commonly exhibits the +2 oxidation state in compounds. It forms oxides such as NiO and various halides like NiCl2. It bonds with carbon and forms a range of alloys, notably cupronickel, Monel, Inconel, and nickel steel.

History and safety: Nickel was discovered in 1751 by Axel Fredrik Cronstedt from the mineral niccolite. The name derives from Kupfernickel, or “false copper.” Exposure to nickel and many of its compounds can cause skin sensitization and respiratory problems; some nickel compounds are considered carcinogenic when inhaled. Nickel is not regarded as essential for human biology.