Nikeli

Nikeli, or nickel (Ni), is a silvery-white, hard, and malleable transition metal with atomic number 28. It is ferromagnetic at room temperature and highly resistant to corrosion due to a protective oxide film. Nickel readily forms compounds such as nickel oxide (NiO) and nickel sulfide (NiS) and serves as a catalyst in several chemical processes.

Natural occurrence and production: Nickel is the fourth or fifth most abundant element in the Earth's core and about 0.008% of the Earth's crust. It is mainly extracted from sulfide ores such as pentlandite and from lateritic ores. Major producers include Russia, Canada, Australia, Indonesia, and New Caledonia. Refining typically involves smelting to produce matte, followed by electrolytic refining to yield high-purity nickel metal.

Applications: Nickel is a key constituent of stainless steels and many corrosion-resistant alloys. It is used in electroplating and nickel plating, batteries (nickel-based) including NiCd and NiMH, and in some lithium-ion cathodes with nickel-rich formulations. Nickel alloys such as Monel and Inconel are valued for strength at high temperatures and corrosion resistance. Nickel also serves as a catalyst in hydrogenation and other reactions.

Health and safety: Exposure to nickel compounds is linked to cancer risk; inhalation of nickel compounds is classified as carcinogenic. Skin contact can cause allergic dermatitis in susceptible individuals. Proper ventilation and protective equipment are advised in industrial settings, and recycling reduces environmental impact.

History and name: Nickel was discovered in 1751 by Axel Fredrik Cronstedt. The ore copper-nickel was named kupfernickel by German miners, meaning devil's copper, from which the element took its name nickel.