Nickel

[[File:Ni@CNT2.jpg |Ni@CNT2

Widmanstatten hand

Nickel-tetracarbonyl-2D

Structure of hexacyanodinickelate(I) ion

Color of various Ni(II) complexes in aqueous solution

Nickel(II)-sulfate-hexahydrate-sample

Nickel is a chemical element with the symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion (passivation). Nickel's physical and chemical properties make it essential in thousands of applications, particularly in stainless steel, magnets, coinage, and special alloys.

Properties

Nickel has a face-centered cubic crystal structure, which is common among transition metals. It is resistant to corrosion, which makes it useful in the production of coins and as a coating for less durable metals. Its ability to withstand extreme temperatures and its high electrical conductivity also make it valuable in the production of products ranging from electric guitar strings to aerospace components.

Occurrence

Nickel is the fifth most common element on Earth and exists in the Earth's crust in concentrated deposits that are mined in over 20 countries. The largest deposits of nickel are found in New Caledonia, Canada, Australia, Indonesia, and Russia. Nickel is also found in meteorites and may have been crucial in the formation of the Earth's crust.

Production

Nickel is primarily extracted from two types of ores, sulfidic and lateritic. The majority of the world's nickel is produced from lateritic ores, but sulfidic ores, which are mined in Canada, Russia, and Australia, provide a significant amount of the world's nickel supply. The production of nickel involves complex processes, including extraction, concentration, smelting, and refining, to produce nickel that is suitable for commercial use.

Applications

Nickel is used in many applications, from household items to high-tech industry products. The largest use of nickel is in the production of stainless steel, which accounts for more than half of the nickel consumed in the world. Nickel is also used in batteries, including rechargeable nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries. Other applications include plating, alloys (such as Inconel, Monel, and Nichrome), and catalysts in chemical production.

Health and Environmental Effects

Nickel compounds are classified as carcinogens by the International Agency for Research on Cancer and can cause allergic reactions such as nickel dermatitis. Exposure to nickel and its compounds may occur through the air, water, and soil, leading to potential health risks for humans and wildlife. Efforts to minimize the environmental and health impacts of nickel include regulations on emissions and advancements in recycling technologies.

Recycling

Nickel is highly recyclable, and recycling plays a significant role in its supply chain. Recycled nickel is an important source of the metal and is used in various applications, including the production of stainless steel. Recycling not only conserves natural resources but also reduces the environmental impact associated with nickel mining and processing.