Nickel

• 1. Introduction

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  Nickel, element 28 on the periodic table, takes its name from a mischievous sprite of German miner mythology. In the ore mountains of medieval Germany, miners kept finding a metallic yellow mineral that looked exactly like copper ore. They smelted it, worked it, and got nothing. No copper came out. Frustrated and superstitious, they blamed a spirit they called Nickel, a cousin of Old Nick, for bewitching the rock. They named the deceiving ore Kupfernickel: Nickel's copper. What the miners could not have known was that the demon they cursed would one day power electric vehicles, hold together skyscrapers, and show up in the coins that jingle in pockets around the world. How did a mineral that tricked medieval miners become one of the most strategically important metals on Earth? And what does it mean that the element is both a known allergen and an essential enzyme ingredient? Those questions carry us through the story of a metal far stranger than its silver surface suggests.

• 2. Born in Stars

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  Nickel-62 holds a distinction that makes it unique among all nuclides: it has the highest binding energy per nucleon of any known nucleus, at 8.7946 MeV per nucleon. That fact sounds like a physics footnote, but it tells you something profound about where nickel comes from. Iron is commonly cited as the endpoint of stellar fusion, yet nickel-62 actually holds its nucleus together more tightly than iron-56 does. The reason nickel does not pile up in the universe the way iron does comes down to a violent process inside stellar interiors: photodisintegration. In the intense radiation of a dying star, nickel nuclei get blasted apart almost as fast as they form, and iron escapes that fate more readily.

  Nickel-56 takes a starring role in the most dramatic light shows the universe produces. Silicon burning generates radioactive nickel-56 in abundance, and when a Type Ia supernova erupts, that nickel-56 is released in enormous quantities. The shape of a supernova's light curve at intermediate to late times traces directly to the decay of nickel-56 through cobalt-56 and ultimately to iron-56. In other words, astronomers studying the brightness of distant stellar explosions are really watching nickel decay in slow motion.

  Nickel-60 carries a different kind of cosmic clock. It is the daughter product of a now-extinct radionuclide with a half-life of about 2.6 million years. Because the parent isotope persisted long enough to leave measurable traces in Solar System material, variations in nickel-60 abundance across extraterrestrial samples can yield clues about the conditions that prevailed when the Sun and planets first formed. And at the exotic fringes of the nuclear chart, nickel-48, discovered in 1999, holds the distinction of being the most proton-rich heavy element isotope ever identified; with 28 protons and just 20 neutrons, it is called doubly magic, a configuration of unusual nuclear stability.

• 3. Metal Beneath Our Feet

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  The deepest nickel on Earth is beyond any drill. Geophysical evidence points to Earth's outer and inner cores as home to the vast majority of the planet's nickel, locked in an iron-nickel mixture far below the crust. What reaches the surface comes partly from above, carried by meteorites. In 1799, the French chemist Joseph-Louis Proust, then working in Spain, became the first person to detect nickel in a meteorite. He analyzed samples from Campo del Cielo in Argentina, a meteorite that had been collected in 1783 by Miguel Rubin de Celis, and found roughly 10% nickel alongside iron.

  On dry land, nickel ores split into two main families. Laterites, which form when tropical weathering strips away other minerals and concentrates nickel near the surface, account for about 60% of identified land-based resources. Sulfide deposits, denser and often deeper, make up the remaining 40%. The most economically important sulfide ore is pentlandite. As of 2024, total identified land-based resources averaging at least 1% nickel add up to at least 130 million tonnes. Indonesia leads world production at roughly 2.2 million tonnes per year, followed by the Philippines, Russia, Canada, China, and Australia.

  The seafloor holds another trove. In the Clarion Clipperton Zone of the Pacific Ocean, polymetallic nodules sit on the seafloor at depths of 3.5 to 6 kilometers. Those nodules contain an estimated 1.7% nickel, alongside numerous rare-earth metals. The International Seabed Authority is currently setting regulations to govern any eventual recovery of those nodules in line with United Nations Sustainable Development Goals.

• 4. The Sprite That Named an Element

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  In 1751, Baron Axel Fredrik Cronstedt traveled to a cobalt mine in the village of Los in Hälsingland, Sweden, armed with the same expectations the medieval miners had carried: he expected Kupfernickel to yield copper. Instead, he extracted a white metal unlike anything he had seen. He named it nickel, borrowing the spirit's name from the ore, and classified it as a new element. His mistake turned out to be one of the more productive errors in the history of chemistry.

  For decades after Cronstedt's classification, nickel remained a curiosity. Its only reliable source was the rare Kupfernickel ore. That changed in 1824 when nickel began to emerge as a byproduct of cobalt blue production. Large-scale smelting launched in Norway in 1848, drawing on nickel-rich pyrrhotite deposits. The pivot that truly transformed nickel from a curio into an industrial necessity came in 1889, when its introduction into steel production sent demand surging. The nickel deposits of New Caledonia, discovered in 1865, supplied most of the world's needs between 1875 and 1915. Then three major finds reset the geography of the industry: the Sudbury Basin in Canada in 1883, Norilsk-Talnakh in Russia in 1920, and the Merensky Reef in South Africa in 1924.

• 5. The Mond Process

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  Ludwig Mond discovered nickel tetracarbonyl, and the find handed the world a way to purify nickel to a purity greater than 99.99%. The process Mond patented has been in industrial use since before the turn of the 20th century. Nickel is treated with carbon monoxide in the presence of a sulfur catalyst at temperatures between roughly 40 and 80 degrees Celsius. The result is nickel carbonyl, a volatile liquid at room temperature. Heating that compound causes it to decompose back into nickel and carbon monoxide, depositing pure nickel.

  In one version of the process, the carbonyl gas is passed through a large chamber where tens of thousands of nickel pellets are constantly stirred. The carbonyl decomposes on contact with the spheres and coats them with pure metal. In a second version, decomposition happens at 230 degrees Celsius in a smaller chamber, producing a fine nickel powder instead. In both cases the carbon monoxide released is recirculated and reused. The product is known as carbonyl nickel. Nickel tetracarbonyl itself is not merely a processing intermediate: as a highly toxic, volatile compound, it represents one of the more hazardous substances in industrial metallurgy, and the same toxicity principle extends to nickel carbonyl's explosive behavior in air.

• 6. Coins and Currency

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  Nickel's relationship with coinage stretches back to the 2nd century BCE, when Bactrian kings Agathocles, Euthydemus II, and Pantaleon minted coins of nickel-copper alloy, possibly drawing on Chinese cupronickel supplies. That early use faded for centuries. Modern coinage adoption began in 1881, when Switzerland introduced coins of nearly pure nickel. Canada struck 99.9% nickel five-cent pieces from 1922 to 1981, making those coins magnetic, a property unique in their era. During the war years 1942 through 1945, both Canada and the United States stripped nickel from their coins entirely to redirect the metal toward armor.

  In the United States, the word nickel as a name for a coin migrated across several denominations. It first attached to the copper-nickel Flying Eagle cent from 1857 to 1858, then to the Indian Head cent through 1864, then to a three-cent nickel in 1865, and finally in 1866 to the five-cent shield nickel at 25% nickel and 75% copper. That alloy proportion, still used today, is not ferromagnetic.

  By April 2007, the metal value inside a US nickel coin had climbed past its face value: the coin contained roughly 0.04 ounces of nickel and 3.75 grams of copper, together worth more than 9 cents against a face value of 5 cents. The United States Mint responded on the 14th of December 2006 by implementing rules that criminalized the melting and export of cents and nickels, with penalties of up to $10,000 in fines and up to five years in prison. As of the 19th of February 2025, the melt value of a US nickel stands at $0.054, or 108% of face value.

• 7. Alloys, Batteries, and Beyond

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  About 68% of global nickel production flows into stainless steel. The next largest slices are nonferrous alloys at 10%, electroplating at 9%, alloy steel at 7%, foundries at 3%, and a remaining 4% covering batteries and other applications. Within that final category, nickel's role in rechargeable batteries has grown steadily, driven by electric vehicles. Nickel(III) occurs in nickel oxide hydroxide, the cathode material used in nickel-cadmium, nickel-iron, nickel-hydrogen, and nickel-metal hydride batteries, and in some lithium-ion battery designs.

  Nickel's usefulness across engineering fields goes beyond bulk strength. It is magnetostrictive: in a magnetic field, nickel contracts by about 50 parts per million. Alnico magnets, which incorporate nickel alongside aluminum and cobalt, occupy a middle tier of magnetic strength between iron-based permanent magnets and rare-earth magnets. Raney nickel, a finely divided nickel-aluminium alloy, serves as a common catalyst for hydrogenation reactions, including the industrial production of margarine from unsaturated oils. In gas diffusion electrodes for alkaline fuel cells, nickel foam or mesh provides the required combination of conductivity and resistance to corrosion.

  In 2025, QuesTek Innovations and Stoke Space jointly developed a nickel-based superalloy for additive manufacturing capable of surviving the extreme pressures and temperatures of a full-flow staged combustion rocket engine called the Zenith. That application, designed for fully reusable spacecraft launch systems, represents one of the newest frontiers for a metal first identified by a Swedish baron more than two and a half centuries ago.

• 8. Allergy, Toxicity, and Biology

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  Nickel is the top confirmed contact allergen worldwide, a title the American Contact Dermatitis Society formalized in 2008 when it voted nickel Allergen of the Year. Pierced ears are the most common exposure route: earrings release enough nickel to sensitize skin, producing itchy, red contact dermatitis in susceptible people. A 2002 study found that 1 and 2 euro coins released nickel at levels that far exceeded the European Union's standards for skin contact, believed to result from a galvanic reaction. In August 2015, the American Academy of Dermatology estimated that nickel sensitization contributes to a contact dermatitis burden of roughly $1.918 billion annually, affecting nearly 72.29 million people.

  Inhalation presents a more serious hazard. Nickel compounds are classified as human carcinogens based on elevated respiratory cancer rates observed in workers at sulfidic ore refineries. Nickel carbonyl, a compound used in the Mond purification process, is an extremely toxic gas; at 10 milligrams per cubic meter, nickel is immediately dangerous to life and health. The Occupational Safety and Health Administration sets the permissible workplace exposure limit at 1 milligram per cubic meter over an 8-hour workday, while the National Institute for Occupational Safety and Health recommends a stricter limit of 0.015 milligrams per cubic meter.

  On the biological side, nickel was not recognized as biologically active until the 1970s. It is now known to be essential to enzymes in some plants, bacteria, archaea, and fungi. Urease, a nickel enzyme, catalyzes the breakdown of urea into ammonia and carbamate and acts as a virulence factor in certain organisms. Cofactor F430, a nickel-tetrapyrrole coenzyme, sits at the heart of methyl coenzyme M reductase, the enzyme that drives methane production in methanogenic archaea. In one grimmer ecological application, nickel released by Siberian Traps volcanic eruptions is suspected of fueling the growth of Methanosarcina, a methane-producing archaea implicated in the Permian-Triassic extinction event, the largest mass extinction in Earth's known history.