Nickel

Nickel is a chemical element with the symbol Ni and the atomic number 28. It is characterized as a silvery-white, lustrous transition metal with a slight golden tinge.

Physically, nickel is hard, malleable, and ductile, meaning it can be shaped without breaking. It also possesses relatively high electrical and thermal conductivity for a transition metal. One of its most notable physical properties is ferromagnetism. Nickel is one of only four elements that are ferromagnetic at or near room temperature, alongside iron, cobalt, and gadolinium. This means it can be strongly attracted to magnets or become a magnet itself.

The chemical behavior of nickel is defined by its ability to form a passivation layer. While pure nickel is chemically reactive, large pieces react very slowly with air under standard conditions. This slow reaction occurs because a thin layer of nickel oxide forms on the surface. This layer acts as a protective shield that prevents further corrosion.

In terms of its atomic structure, nickel has a face-centered cubic unit cell. It has a lattice parameter of 0.352 nm and an atomic radius of 0.124 nm. This specific crystal structure remains stable even under extreme pressures of at least 70 GPa. Scientists also study its electron configuration, which involves the 3d and 4s energy levels. There is a scientific debate regarding which configuration has the lower energy, as the two states overlap significantly.

Nickel is found in several distinct forms and mineral types. In the Earth's crust, most nickel exists as oxides. These include laterite, which contains minerals like limonite, and garnierite. However, the most economically important nickel ores are sulfides. A primary example is pentlandite, a mineral that often exists in solid solutions with iron.

Another important form is found in natural alloys called kamacite and taenite. Kamacite is usually composed of 90% to 95% iron, while taenite contains between 20% and 65% nickel. These alloys are frequently found in nickel-iron meteorites from space.

The history of nickel discovery involves both mythology and careful chemistry. The name "nickel" actually comes from a mischievous sprite in German miner mythology. Miners used this name for ores like kupfernickel because they looked like copper but produced no copper.

The element was officially isolated and classified in 1751 by Axel Fredrik Cronstedt. He discovered it in the cobalt mines of Los, Hälsingland, Sweden, though he initially mistook the ore for a copper mineral. Later, in 1799, the French chemist Joseph-Louis Proust detected nickel in a meteorite from Campo del Cielo, Argentina. This helped scientists understand that nickel is often found in combination with iron in meteoric material.

Nickel production is a massive global industry with specific geographic hubs. Major production sites include Sulawesi, Indonesia, and the Sudbury region in Canada. Other significant areas include New Caledonia, Western Australia, and Norilsk, Russia.

It is estimated that land-based resources averaging 1% nickel or greater comprise at least 130 million tons. About 60% of these resources are found in laterites, while 40% are in sulfide deposits. While we mine it from the crust, much of the Earth's nickel is actually located deep within the planet. Geophysics suggests that an iron-nickel mixture composes both the outer and inner cores of the Earth.

Modern society relies on nickel for a wide variety of industrial applications. The largest use is for stainless steel, which accounts for approximately 68% of world production.

Another 10% is used for nickel-based or copper-based alloys, and 9% is used for plating. About 4% of nickel is used in rechargeable batteries, including those found in electric vehicles.

Nickel is also used to create Alnico permanent magnets. These magnets have an intermediate strength that sits between iron-based magnets and rare-earth magnets. Additionally, nickel is used in coins and as a catalyst for chemical processes like hydrogenation.

Beyond industry, nickel plays a role in both biology and deep space science. For some microorganisms and plants, nickel is an essential nutrient. It is used as an active site in certain enzymes to help biological processes function. In the stars, nickel is part of a complex cycle. While nickel-62 has the highest binding energy per nucleon of any nuclide, nickel is not the most abundant heavy element in the universe. This is because the high rate of photodisintegration in stellar interiors causes iron to be more abundant. However, studying nickel isotopes like nickel-59 can provide scientists with insights into the early history and origin of our Solar System.