ABSTRACT
Nickel (Ni) is a major component of the Earth's core but much less is present in the crust. Nickel has an affinity for organic matter and is present in oil and coal. Meteorites are typically rich in Nickel, containing 1-2% on average and form the major natural source of metallic Nickel at the Earth's surface. Nickel is essential in plants for normal growth. The ionic radius of Nickel is similar to iron and some other micronutrients and it can replace them in enzymes. Nickel may be purified by the Mond process: first Nickel oxide is reduced by reaction with H2 to create impure Nickel, which is then reacted with carbon monoxide to produce Nickel carbonyl; the latter is then decomposed by heating, leaving pure Nickel. The main uses of Nickel are stainless steel and the Ni-superalloys, especially Nickel aluminide, which resist corrosion and are stable at high temperatures.
