nikel

Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white, hard, ductile metal that is ferromagnetic at room temperature. Its Curie point is about 355°C, above which it loses ferromagnetism. Nickel resists corrosion because it rapidly forms a protective oxide layer in air.

Nickel occurs chiefly in sulfide and laterite ores, notably pentlandite and garnierite. Major producers include Russia, Canada, Australia and Indonesia, with significant mines in the Sudbury basin and Norilsk region. Ore concentrates are produced by flotation, then smelted and refined; high-purity nickel can be obtained by the Mond process, which converts nickel to nickel carbonyl and back.

The metal is a key constituent of stainless steels and many nickel-based alloys such as Monel, Inconel, and Nichrome. It is used in plating, coinage, and catalysts, and in rechargeable batteries (nickel–cadmium and nickel–metal hydride).

Named after the German kupfernickel, meaning devil's copper, the element was isolated by Axel Cronstedt in 1751. The term nickel arose from the ore’s misleading copper-like appearance.

Health and environmental aspects: Exposure to nickel and its compounds can cause allergic dermatitis and other health effects; occupational exposure is regulated in many countries. Nickel is a relatively abundant element in Earth's crust and occurs naturally in minerals and meteoritic iron.