Nickel

Nickel (chemical symbol Ni) is a transition metal with a silvery-white, lustrous appearance. It is hard, ductile and malleable, and is an excellent conductor of electricity and heat. Nickel is ferromagnetic at room temperature—one of a small number of elements with this property.

Nickel belongs to the transition metals on the periodic table. It develops a protective oxide layer on its surface, which helps it resist corrosion. For this reason, its primary use is in the production of alloys, particularly stainless steel.

Chemical properties

Nickel is in group 10 of the periodic table, between cobalt and copper. Its atomic number is 28. Its highest oxidation state is +2, as in compounds such as NiSO4 and NiCl2, which typically form greenish solutions in water. It reacts with dilute acids readily and is resistant to air and water at ordinary temperatures.

Extraction and production

Nickel ore comes from two main types: sulfide ores (such as pentlandite) and laterite ores found in tropical regions. Production involves crushing, concentration, roasting or acid leaching, followed by electrorefining to obtain pure nickel. Major producing countries include Indonesia, the Philippines, Russia, Canada and Australia.

Uses

The largest share of nickel is used in the manufacture of stainless steel and other alloys such as nichrome (nickel and chromium) for heating elements. It is also used in electroplating, coins, and chemical catalysts such as those for hydrogenation of oils. In recent decades, nickel-based batteries—such as nickel-metal hydride and lithium-ion batteries with nickel-rich cathodes—have increased demand for the metal, particularly in electric vehicles.

Health and environment

Nickel allergy is common and occurs when the skin comes into contact with nickel-containing objects such as jewelry and watches. Some compounds of nickel that can be inhaled are considered occupational health hazards. Ore mining and smelting can affect air and water quality if not properly managed.