Use of nickel (as naturalmeteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classified as an element in 1751 byAxel Fredrik Cronstedt, who initially mistook theore for acoppermineral, in the cobalt mines ofLos, Hälsingland, Sweden. The element's name comes from a mischievous sprite of German miner mythology, Nickel (similar toOld Nick). Nickel minerals can be green, like copper ores, and were known as kupfernickel – Nickel's copper – because they produced no copper.
Nickel is one of four elements (the others areiron,cobalt, andgadolinium)[14] that areferromagnetic at about room temperature.Alnico permanentmagnets based partly on nickel are of intermediate strength between iron-based permanent magnets andrare-earth magnets. The metal is used chiefly inalloys and corrosion-resistant plating.
About 68% of world production is used instainless steel. A further 10% is used for nickel-based and copper-based alloys, 9% for plating, 7% for alloy steels, 3% in foundries, and 4% in other applications such as in rechargeable batteries,[15] including those inelectric vehicles (EVs).[16] Nickel is widely used incoins, though nickel-plated objects sometimes provokenickel allergy. As a compound, nickel has a number of niche chemical manufacturing uses, such as acatalyst for hydrogenation,cathodes for rechargeable batteries, pigments and metal surface treatments.[17] Nickel is an essential nutrient for some microorganisms and plants that haveenzymes with nickel as anactive site.[18]
Nickel is a silvery-white metal with a slight golden tinge that takes a high polish. It is one of only four elements that areferromagnetic at or near room temperature; the others are iron,cobalt andgadolinium. ItsCurie temperature is 355 °C (671 °F), meaning that bulk nickel is non-magnetic above this temperature.[20][14] The unit cell of nickel is aface-centered cube; it has lattice parameter of 0.352 nm, giving anatomic radius of 0.124 nm. This crystal structure is stable to pressures of at least 70 GPa. Nickel is hard, malleable andductile, and has a relatively highelectrical andthermal conductivity for transition metals.[21] The highcompressive strength of 34 GPa, predicted for ideal crystals, is never obtained in the real bulk material due to formation and movement ofdislocations. However, it has been reached in Ninanoparticles.[22]
Electron configuration dispute
Nickel has two atomicelectron configurations, [Ar] 3d8 4s2 and [Ar] 3d9 4s1, which are very close in energy; [Ar] denotes the completeargon core structure. There is some disagreement on which configuration has the lower energy.[23] Chemistry textbooks quote nickel's electron configuration as [Ar] 4s2 3d8,[24] also written [Ar] 3d8 4s2.[25] This configuration agrees with theMadelung energy ordering rule, which predicts that 4s is filled before 3d. It is supported by the experimental fact that the lowest energy state of the nickel atom is a 3d8 4s2 energy level, specifically the 3d8(3F) 4s23F,J = 4 level.[26][27]
However, each of these two configurations splits into several energy levels due tofine structure,[26][27] and the two sets of energy levels overlap. The average energy of states with [Ar] 3d9 4s1 is actually lower than the average energy of states with [Ar] 3d8 4s2. Therefore, the research literature on atomic calculations quotes the ground state configuration as [Ar] 3d9 4s1.[23]
The isotopes of nickel range inatomic weight from 48 u (48 Ni) to 82 u (82 Ni).[9]
Natural nickel is composed of five stableisotopes,58 Ni,60 Ni,61 Ni,62 Ni and64 Ni, of which58 Ni is the most abundant (68.077%natural abundance).[9]
Nickel-62 has the highestbinding energy per nucleon of anynuclide: 8.7946 MeV/nucleon.[28][29] Its binding energy is greater than both56 Fe and58 Fe, more abundant nuclides often incorrectly cited as having the highest binding energy.[30] Though this would seem to predict nickel as the most abundant heavy element in the universe, the high rate ofphotodisintegration of nickel in stellar interiors causes iron to be by far the most abundant.[30]
Nickel-60 is the daughter product of theextinct radionuclide60 Fe (half-life 2.6 million years). Due to the long half-life of60 Fe, its persistence in materials in theSolar System may generate observable variations in the isotopic composition of60 Ni. Therefore, the abundance of60 Ni in extraterrestrial material may give insight into the origin of the Solar System and its early history.[31]
At least 26 nickelradioisotopes have been characterized; the most stable are59 Ni withhalf-life 76,000 years,63 Ni (100 years), and56 Ni (6 days). All other radioisotopes have half-lives less than 60 hours and most these have half-lives less than 30 seconds. This element also has onemeta state.[9]
Radioactive nickel-56 is produced by thesilicon burning process and later set free in large amounts intype Iasupernovae. The shape of thelight curve of these supernovae at intermediate to late-times corresponds to the decay viaelectron capture of56 Ni tocobalt-56 and ultimately to iron-56.[32] Nickel-59 is a long-livedcosmogenicradionuclide; half-life 76,000 years.59 Ni has found many applications inisotope geology.59 Ni has been used to date the terrestrial age ofmeteorites and to determine abundances of extraterrestrial dust in ice andsediment. Nickel-78, with a half-life of 110 milliseconds, is believed an important isotope insupernova nucleosynthesis of elements heavier than iron.[33]48Ni, discovered in 1999, is the most proton-rich heavy element isotope known. With 28protons and 20neutrons,48Ni is "doubly magic", as is78Ni with 28 protons and 50 neutrons. Both are therefore unusually stable for nuclei with so large aproton–neutron imbalance.[9][34]
Nickel-63 is a contaminant found in the support structure of nuclear reactors. It is produced through neutron capture by nickel-62. Small amounts have also been found near nuclear weapon test sites in the South Pacific.[35]
Widmanstätten pattern showing the two forms of nickel–iron, kamacite and taenite, in an octahedrite meteorite
Nickel ores are classified as oxides or sulfides. Oxides includelaterite, where the principal mineral mixtures are nickeliferouslimonite, (Fe,Ni)O(OH), andgarnierite (a mixture of various hydrous nickel and nickel-rich silicates).[36] Nickel sulfides commonly exist as solid solutions with iron in minerals such aspentlandite andpyrrhotite with the formula Fe9−xNixS8 and Fe7−xNixS6, respectively. Other common Ni-containing minerals aremillerite and thearsenideniccolite.[37][38]
Identified land-based resources throughout the world averaging 1% nickel or greater comprise at least 130 million tons of nickel (about the double of known reserves). About 60% is inlaterites and 40% in sulfide deposits.[39]
Ongeophysical evidence, most of the nickel on Earth is believed to be in Earth'souter andinner cores.Kamacite andtaenite are naturally occurringalloys of iron and nickel. For kamacite, the alloy is usually in the proportion of 90:10 to 95:5, though impurities (such ascobalt orcarbon) may be present. Taenite is 20% to 65% nickel. Kamacite and taenite are also found innickel iron meteorites.[40]
Nickel is commonly found iniron meteorites as the alloyskamacite andtaenite. Nickel in meteorites was first detected in 1799 byJoseph-Louis Proust, a French chemist who then worked in Spain. Proust analyzed samples of the meteorite fromCampo del Cielo (Argentina), which had been obtained in 1783 by Miguel Rubín de Celis, discovering the presence in them of nickel (about 10%) along with iron.[41]
The most commonoxidation state of nickel is +2, but compounds ofNi0,Ni+, andNi3+ are well known, and the exotic oxidation statesNi2− andNi− have been characterized.[42]
Nickel(0)
Tetracarbonyl nickel
Nickel tetracarbonyl(Ni(CO)4), discovered byLudwig Mond,[43] is a volatile, highly toxic liquid at room temperature. On heating, the complex decomposes back to nickel and carbon monoxide:
Nickel(I) complexes are uncommon, but one example is the tetrahedral complexNiBr(PPh3)3. Many nickel(I) complexes have Ni–Ni bonding, such as the dark reddiamagneticK4[Ni2(CN)6] prepared by reduction ofK2[Ni2(CN)6] withsodium amalgam. This compound is oxidized in water, liberatingH2.[44]
It is thought that the nickel(I) oxidation state is important to nickel-containing enzymes, such as[NiFe]-hydrogenase, which catalyzes the reversible reduction ofprotons toH2.[45]
Nickel(II)
Color of various Ni(II) complexes in aqueous solution. From left to right,[Ni(NH3)6]2+,[Ni(NH2CH2CH2NH2)]2+,[Ni(H2O)5Cl]+,[Ni(H2O)6]2+Crystals ofhydratednickel(II) sulfate
Nickel(II) forms compounds with all common anions, includingsulfide,sulfate, carbonate, hydroxide, carboxylates, and halides.Nickel(II) sulfate is produced in large amounts by dissolving nickel metal or oxides insulfuric acid, forming both a hexa- and heptahydrate[46] useful forelectroplating nickel. Common salts of nickel, such as chloride, nitrate, and sulfate, dissolve in water to give green solutions of themetal aquo complex[Ni(H2O)6]2+.[47]
The four halides form nickel compounds, which are solids with molecules with octahedral Ni centres.Nickel(II) chloride is most common, and its behavior is illustrative of the other halides. Nickel(II) chloride is made by dissolving nickel or its oxide inhydrochloric acid. It is usually found as the green hexahydrate, whose formula is usually writtenNiCl2·6H2O. When dissolved in water, this salt forms themetal aquo complex[Ni(H2O)6]2+. Dehydration ofNiCl2·6H2O gives yellow anhydrousNiCl2.[48]
Some tetracoordinate nickel(II) complexes, e.g.bis(triphenylphosphine)nickel chloride, exist both in tetrahedral and square planar geometries. The tetrahedral complexes areparamagnetic; the square planar complexes arediamagnetic. In having properties of magnetic equilibrium and formation of octahedral complexes, they contrast with the divalent complexes of the heavier group 10 metals, palladium(II) and platinum(II), which form only square-planar geometry.[42]
Nickelocene has anelectron count of 20. Many chemical reactions of nickelocene tend to yield 18-electron products.[49]
Nickel(III) and (IV)
Nickel(III) antimonide
Many Ni(III) compounds are known. Ni(III) forms simple salts with fluoride[50] oroxide ions. Ni(III) can be stabilized by σ-donor ligands such asthiols andorganophosphines.[44]
Ni(IV) remains a rare oxidation state and very few compounds are known. Ni(IV) occurs in the mixed oxideBaNiO3.[52][53][54][55]
Nickel(VI)
As of 2024, hexavalent nickel is known in the form of crystalline Ni(BeCp)6. Notably it is not octahedral, instead adopting C3v geometry.[56]
History
Unintentional use of nickel can be traced back as far as 3500 BCE.[57]Bronzes from what is now Syria have been found to contain as much as 2% nickel.[58] Some ancient Chinese manuscripts suggest that "white copper" (cupronickel, known asbaitong) was used there in 1700–1400 BCE. This Paktong white copper was exported to Britain as early as the 17th century, but the nickel content of this alloy was not discovered until 1822.[59] Coins of nickel-copper alloy were minted by Bactrian kingsAgathocles,Euthydemus II, andPantaleon in the 2nd century BCE, possibly out of the Chinese cupronickel.[60]
Nickeline/niccolite
In medieval Germany, a metallic yellow mineral was found in theOre Mountains that resembled copper ore. But when miners were unable to get any copper from it, they blamed a mischievous sprite of German mythology, Nickel (similar toOld Nick), for besetting the copper. They called this oreKupfernickel from GermanKupfer 'copper'.[61][62][63][64] This ore is now known as the mineralnickeline (formerlyniccolite[65]), a nickelarsenide. In 1751, BaronAxel Fredrik Cronstedt tried to extract copper from kupfernickel at acobalt mine in the village ofLos, Sweden, and instead produced a white metal that he namednickel after the spirit that had given its name to the mineral.[66] In modern German, Kupfernickel or Kupfer-Nickel designates the alloycupronickel.[21]
Originally, the only source for nickel was the rare Kupfernickel. Beginning in 1824, nickel was obtained as a byproduct ofcobalt blue production. The first large-scale smelting of nickel began in Norway in 1848 from nickel-richpyrrhotite.[67] The introduction of nickel in steel production in 1889 increased the demand for nickel; the nickel deposits ofNew Caledonia, discovered in 1865, provided most of the world's supply between 1875 and 1915. The discovery of the large deposits in theSudbury Basin in Canada in 1883, inNorilsk-Talnakh in Russia in 1920, and in theMerensky Reef in South Africa in 1924 made large-scale nickel production possible.[59]
Aside from the aforementioned Bactrian coins, nickel was not a component of coins until the mid-19th century.[68]
Canada
99.9% nickel five-cent coins were struck in Canada (the world's largest nickel producer at the time) during non-war years from 1922 to 1981; the metal content made these coins magnetic.[69] During the war years 1942–1945, most or all nickel was removed from Canadian and US coins to save it for making armor.[62] Canada used 99.9% nickel from 1968 in its higher-value coins until 2000.[70]
Switzerland
Coins of nearly pure nickel were first used in 1881 in Switzerland.[71]
In the United States, the term "nickel" or "nick" originally applied to the copper-nickelFlying Eagle cent, which replaced copper with 12% nickel 1857–58, then theIndian Head cent of the same alloy from 1859 to 1864. Still later, in 1865, the term designated thethree-cent nickel, with nickel increased to 25%. In 1866, thefive-cent shield nickel (25% nickel, 75% copper) appropriated the designation, which has been used ever since for the subsequent 5-cent pieces. This alloy proportion is notferromagnetic.
TheUS nickel coin contains 0.04 ounces (1.1 g) of nickel, which at the April 2007 price was worth 6.5 cents, along with 3.75 grams of copper worth about 3 cents, with a total metal value of more than 9 cents. Since the face value of a nickel is 5 cents, this made it an attractive target for melting by people wanting to sell the metals at a profit. TheUnited States Mint, anticipating this practice, implemented new interim rules on December 14, 2006, subject to public comment for 30 days, which criminalized the melting and export of cents and nickels.[73] Violators can be punished with a fine of up to $10,000 and/or a maximum of five years in prison.[74] As of February 19, 2025, the melt value of a US nickel (copper and nickel included) is $0.054 (108% of the face value).[75]
Current use
In the 21st century, the high price of nickel has led to some replacement of the metal in coins around the world. Coins still made with nickel alloys include one- and two-euro coins, 5¢, 10¢, 25¢, 50¢, and $1U.S. coins,[76] and 20p, 50p, £1, and £2UK coins. From 2012 on the nickel-alloy used for 5p and 10p UK coins was replaced with nickel-plated steel. This ignited a public controversy regarding the problems of people withnickel allergy.[71]
World production
Time trend of nickel production[77]Nickel ores grade evolution in some leading nickel producing countries or regions
An estimated 3.7 million tonnes (t) of nickel per year are mined worldwide;Indonesia (2,200,000 t), thePhilippines (330,000 t),Russia (210,000 t),Canada (190,000 t),China (120,000 t), andAustralia (110,000 t) are the largest producers as of 2024.[78] The largest nickel deposits in non-Russian Europe are inFinland andGreece. Identified land-based sources averaging at least 1% nickel contain at least 130 million tonnes of nickel. About 60% is in laterites and 40% is in sulfide deposits. Also, extensive nickel sources are found in the depths of thePacific Ocean, especially in an area called theClarion Clipperton Zone in the form ofpolymetallic nodules peppering theseafloor at 3.5–6 km belowsea level.[79][80] These nodules are composed of numerousrare-earth metals and are estimated to be 1.7% nickel.[81] With advances in science andengineering, regulation is currently being set in place by theInternational Seabed Authority to ensure that these nodules are collected in an environmentally conscientious manner while adhering to theUnited NationsSustainable Development Goals.[82]
The one place in the United States where nickel has been profitably mined isRiddle, Oregon, with several square miles of nickel-bearinggarnierite surface deposits. The mine closed in 1987.[83][84] TheEagle mine project is a new nickel mine in Michigan'sUpper Peninsula. Construction was completed in 2013, and operations began in the third quarter of 2014.[85] In the first full year of operation, the Eagle Mine produced 18,000 t.[85] The Eagle mine produced 17,000 tons of nickel concentrate in 2023.[86] Other projects in the region include theMarquette County nickel project, which received $145 million in funding from the federal government in 2024,[87] investments in work at the Boulderdash and Roland mines,[88] and the development of a third zone, the Keel zone, at The Eagle mine.[89]
Production
Evolution of the annual nickel extraction, according to ores
Nickel is obtained throughextractive metallurgy: it is extracted from ore by conventional roasting and reduction processes that yield metal of greater than 75% purity. In manystainless steel applications, 75% pure nickel can be used without further purification, depending on impurities.[46]
Traditionally, most sulfide ores are processed usingpyrometallurgical techniques to produce amatte for further refining.Hydrometallurgical techniques are also used. Most sulfide deposits have traditionally been processed by concentration through afroth flotation process followed by pyrometallurgical extraction. The nickel matte is further processed with theSherritt-Gordon process. First, copper is removed by addinghydrogen sulfide, leaving a concentrate of cobalt and nickel. Then, solvent extraction is used to separate the cobalt and nickel, with the final nickel content greater than 86%.[90]
A second common refining process is leaching the metal matte into a nickel salt solution, followed byelectrowinning the nickel from solution by plating it onto a cathode as electrolytic nickel.[91]
Mond process
Highly purified nickel spheres made by theMond process
The purest metal is obtained from nickel oxide by theMond process, which gives a purity of over 99.99%. The process was patented byLudwig Mond and has been in industrial use since before the beginning of the 20th century.[92] In this process, nickel is treated withcarbon monoxide in the presence of a sulfur catalyst at around 40–80 °C to formnickel carbonyl. In a similar reaction with iron,iron pentacarbonyl can form, though this reaction is slow. If necessary, the nickel may be separated by distillation.Dicobalt octacarbonyl is also formed in nickel distillation as a by-product, but it decomposes totetracobalt dodecacarbonyl at the reaction temperature to give a non-volatile solid.[13]
Nickel is obtained from nickel carbonyl by one of two processes. It may be passed through a large chamber at high temperatures in which tens of thousands of nickel spheres (pellets) are constantly stirred. The carbonyl decomposes and deposits pure nickel onto the spheres. In the alternate process, nickel carbonyl is decomposed in a smaller chamber at 230 °C to create a fine nickel powder. The byproduct carbon monoxide is recirculated and reused. The highly pure nickel product is known as "carbonyl nickel".[93]
Market value
The market price of nickel surged throughout 2006 and the early months of 2007; as of April 5, 2007[update], the metal was trading atUS$52,300/tonne or $1.47/oz.[94] The price later fell dramatically; as of September 2017[update], the metal was trading at $11,000/tonne, or $0.31/oz.[95] During the2022 Russian invasion of Ukraine, worries about sanctions on Russian nickel exports triggered ashort squeeze, causing the price of nickel to quadruple in just two days, reaching US$100,000 per tonne.[96][97] TheLondon Metal Exchange cancelled contracts worth $3.9 billion and suspended nickel trading for over a week.[98] Analyst Andy Home argued that such price shocks are exacerbated by the purity requirements imposed by metal markets: only Grade I (99.8% pure) metal can be used as acommodity on the exchanges, but most of the world's supply is either inferro-nickel alloys or lower-grade purities.[99] In 2024, the average nickel price is estimated by theLondon Metal Exchange (LME) to be $15,328 per metric ton, 7.7% less than it was in 2023. At the end of 2024, the price reached its lowest levels since 2020.[100]
Applications
Nickel foam (top) and its internal structure (bottom)
Global use of nickel is currently 68% in stainless steel, 10% in nonferrousalloys, 9%electroplating, 7% alloy steel, 3% foundries, and 4% other (including batteries).[15]
Nickel is used in many recognizable industrial and consumer products, includingstainless steel,alnico magnets, coinage,rechargeable batteries (e.g.nickel–iron), electric guitar strings, microphone capsules, plating on plumbing fixtures,[101] and special alloys such aspermalloy,elinvar, andinvar. It is used for plating and as a green tint in glass. Nickel is preeminently an alloy metal, and its chief use is in nickel steels and nickel cast irons, in which it typically increases the tensile strength, toughness, and elastic limit. It is widely used in many other alloys, including nickel brasses and bronzes and alloys with copper, chromium, aluminium, lead, cobalt, silver, and gold (Inconel,Incoloy,Monel,Nimonic).[91]
Nickel is traditionally used forKris production in Southeastern Asia.
Because nickel is resistant to corrosion, it was occasionally used as a substitute for decorative silver. Nickel was also occasionally used in some countries after 1859 as a cheap coinage metal (see above), but in the later years of the 20th century, it was replaced by cheaper stainless steel (i.e., iron) alloys, except in the United States and Canada.[68]
Nickel is an excellent alloying agent for certain precious metals and is used in thefire assay as a collector ofplatinum group elements (PGE). As such, nickel can fully collect all six PGEs from ores, and can partially collect gold. High-throughput nickel mines may also do PGE recovery (mainlyplatinum andpalladium); examples are Norilsk, Russia and the Sudbury Basin, Canada.[102]
Nickel and its alloys are often used as catalysts forhydrogenation reactions.Raney nickel, a finely divided nickel-aluminium alloy, is one common form, though related catalysts are also used, including Raney-type catalysts.[105]
Nickel is naturally magnetostrictive: in the presence of amagnetic field, the material undergoes a small change in length.[106][107] Themagnetostriction of nickel is on the order of 50 ppm and is negative, indicating that it contracts.[108]
Nickel is used as a binder in the cementedtungsten carbide or hardmetal industry and used in proportions of 6% to 12% by weight. Nickel makes the tungsten carbide magnetic and adds corrosion-resistance to the cemented parts, though the hardness is less than those with cobalt binder.[109]
Around 27% of all nickel production is used for engineering, 10% for building and construction, 14% for tubular products, 20% for metal goods, 14% for transport, 11% for electronic goods, and 5% for other uses.[15]
Raney nickel is widely used forhydrogenation ofunsaturated oils to makemargarine, and substandard margarine and leftover oil may contain nickel as acontaminant. Forte et al. found that type 2 diabetic patients have 0.89 ng/mL of Ni in the blood relative to 0.77 ng/mL in control subjects.[113]
It was not recognized until the 1970s, but nickel is known to play an important role in the biology of some plants,bacteria,archaea, andfungi.[114][115][116] Nickel enzymes such asurease are considered virulence factors in some organisms.[117][118] Urease catalyzes hydrolysis ofurea to formammonia andcarbamate.[115][114]NiFe hydrogenases can catalyze oxidation ofH2 to form protons and electrons; and also the reverse reaction, the reduction of protons to form hydrogen gas.[115][114] A nickel-tetrapyrrole coenzyme,cofactor F430, is present in methylcoenzyme M reductase, which can catalyze the formation of methane, or the reverse reaction, inmethanogenicarchaea (in +1 oxidation state).[119] One of the carbon monoxide dehydrogenase enzymes consists of anFe-Ni-S cluster.[120] Other nickel-bearing enzymes include a rare bacterial class ofsuperoxide dismutase[121] andglyoxalase I enzymes in bacteria and several eukaryotictrypanosomal parasites[122] (in other organisms, including yeast and mammals, this enzyme contains divalentZn2+).[123][124][125][126][127]
Dietary nickel may affect human health through infections by nickel-dependent bacteria, but nickel may also be an essential nutrient for bacteria living in the large intestine, in effect functioning as aprebiotic.[128] The US Institute of Medicine has not confirmed that nickel is an essential nutrient for humans, so neither aRecommended Dietary Allowance (RDA) nor an Adequate Intake have been established. Thetolerable upper intake level of dietary nickel is 1 mg/day as soluble nickel salts. Estimated dietary intake is 70 to 100 μg/day; less than 10% is absorbed. What is absorbed is excreted in urine.[129] Relatively large amounts of nickel – comparable to the estimated average ingestion above –leach into food cooked in stainless steel. For example, the amount of nickel leached after 10 cooking cycles into one serving of tomato sauce averages 88 μg.[130][131]
The major source of nickel exposure is oral consumption, as nickel is essential to plants.[134] Typical background concentrations of nickel do not exceed 20 ng/m3 in air, 100 mg/kg in soil, 10 mg/kg in vegetation, 10 μg/L in freshwater and 1 μg/L in seawater.[135] Environmental concentrations may be increased by humanpollution. For example, nickel-platedfaucets may contaminate water and soil;mining and smelting may dump nickel intowastewater; nickel–steelalloy cookware and nickel-pigmented dishes may release nickel into food. Air may be polluted by nickel ore refining andfossil fuel combustion. Humans may absorb nickel directly fromtobacco smoke and skin contact with jewelry,shampoos, detergents, andcoins. A less common form of chronic exposure is throughhemodialysis as traces of nickel ions may be absorbed into the plasma from thechelating action ofalbumin.[citation needed]
The average daily exposure is not a threat to human health. Most nickel absorbed by humans is removed by the kidneys and passed out of the body through urine or is eliminated through the gastrointestinal tract without being absorbed. Nickel is not a cumulative poison, but larger doses or chronic inhalation exposure may be toxic, evencarcinogenic, and constitute anoccupational hazard.[136]
Nickel compounds are classified as human carcinogens[137][138][139][140] based on increased respiratory cancer risks observed in epidemiological studies of sulfidic ore refinery workers.[141] This is supported by the positive results of the NTP bioassays with Ni sub-sulfide and Ni oxide in rats and mice.[142][143] The human and animal data consistently indicate a lack of carcinogenicity via the oral route of exposure and limit the carcinogenicity of nickel compounds to respiratory tumours after inhalation.[144][145] Nickel metal is classified as a suspect carcinogen;[137][138][139] there is consistency between the absence of increased respiratory cancer risks in workers predominantly exposed to metallic nickel[141] and the lack of respiratory tumours in a rat lifetime inhalation carcinogenicity study with nickel metal powder.[146] In the rodent inhalation studies with various nickel compounds and nickel metal, increased lung inflammations with and without bronchial lymph node hyperplasia or fibrosis were observed.[140][142][146][147] In rat studies, oral ingestion of water-soluble nickel salts can trigger perinatal mortality in pregnant animals.[148] Whether these effects are relevant to humans is unclear as epidemiological studies of highly exposed female workers have not shown adverse developmental toxicity effects.[149]
Sensitized persons may show a skin contactallergy to nickel known as a contactdermatitis. Highly sensitized persons may also react to foods with high nickel content.[153] Patients withpompholyx may also be sensitive to nickel. Nickel is the top confirmed contact allergen worldwide, partly due to its use in jewelry forpierced ears.[154] Nickel allergies affecting pierced ears are often marked by itchy, red skin. Many earrings are now made without nickel or with low-release nickel[155] to address this problem. The amount allowed in products that contact human skin is now regulated by theEuropean Union. In 2002, researchers found that the nickel released by 1 and 2 euro coins, far exceeded those standards. This is believed to be due to agalvanic reaction.[156] Nickel was votedAllergen of the Year in 2008 by the American Contact Dermatitis Society.[157] In August 2015, theAmerican Academy of Dermatology adopted a position statement on the safety of nickel: "Estimates suggest that contact dermatitis, which includes nickel sensitization, accounts for approximately $1.918 billion and affects nearly 72.29 million people."[153]
Reports show that both the nickel-induced activation of hypoxia-inducible factor (HIF-1) and the up-regulation of hypoxia-inducible genes are caused by depletion of intracellularascorbate. The addition of ascorbate to the culture medium increased the intracellular ascorbate level and reversed both the metal-induced stabilization of HIF-1- and HIF-1α-dependent gene expression.[158][159]
^abcArblaster, John W. (2018).Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International.ISBN978-1-62708-155-9.
^Ni(–2) is known inNi(COD)2−2; seeJohn E. Ellis (2006). "Adventures with Substances Containing Metals in Negative Oxidation States".Inorganic Chemistry.45 (8):3167–3186.doi:10.1021/ic052110i.
^Ni(0) is known inNi(CO)4; seeJohn E. Ellis (2006). "Adventures with Substances Containing Metals in Negative Oxidation States".Inorganic Chemistry.45 (8):3167–3186.doi:10.1021/ic052110i.
^Pfirrmann, Stefan; Limberg, Christian; Herwig, Christian; Stößer, Reinhard; Ziemer, Burkhard (2009). "A Dinuclear Nickel(I) Dinitrogen Complex and its Reduction in Single-Electron Steps".Angewandte Chemie International Edition.48 (18):3357–61.doi:10.1002/anie.200805862.PMID19322853.
^Carnes, Matthew; Buccella, Daniela; Chen, Judy Y.-C.; Ramirez, Arthur P.; Turro, Nicholas J.; Nuckolls, Colin; Steigerwald, Michael (2009). "A Stable Tetraalkyl Complex of Nickel(IV)".Angewandte Chemie International Edition.48 (2):290–4.doi:10.1002/anie.200804435.PMID19021174.
^Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1990)."Nickel"(PDF).Handbook of Mineralogy. Vol. I. Chantilly, Virginia, US: Mineralogical Society of America.ISBN978-0962209703.
^Stixrude, Lars; Waserman, Evgeny; Cohen, Ronald (November 1997). "Composition and temperature of Earth's inner core".Journal of Geophysical Research.102 (B11):24729–24740.Bibcode:1997JGR...10224729S.doi:10.1029/97JB02125.
^abCoey, J. M. D.; Skumryev, V.; Gallagher, K. (1999). "Rare-earth metals: Is gadolinium really ferromagnetic?".Nature.401 (6748):35–36.Bibcode:1999Natur.401...35C.doi:10.1038/43363.
^Miessler, G.L. and Tarr, D.A. (1999)Inorganic Chemistry 2nd ed., Prentice–Hall. p. 38.ISBN0138418918.
^Petrucci, R.H. et al. (2002)General Chemistry 8th ed., Prentice–Hall. p. 950.ISBN0130143294.
^abCorliss, Charles; Sugar, Jack (October 15, 2009)."Energy levels of nickel, Ni I through Ni XXVIII"(PDF). Journal of Physical and Chemical Reference Data. p. 200. RetrievedMarch 5, 2023.In this table Ni I = neutral Ni atom, Ni II = Ni+ etc.
^Rasmussen, K. L.; Malvin, D. J.; Wasson, J. T. (1988). "Trace element partitioning between taenite and kamacite – Relationship to the cooling rates of iron meteorites".Meteoritics.23 (2): a107–112.Bibcode:1988Metic..23..107R.doi:10.1111/j.1945-5100.1988.tb00905.x.
^Calvo, Miguel (2019).Construyendo la Tabla Periódica. Zaragoza, Spain: Prames. p. 118.ISBN978-84-8321-908-9.
^Miessler, Gary L.; Tarr, Donald A. (1999).Inorganic Chemistry (2nd ed.). Prentice-Hall. pp. 456–457.ISBN0-13-841891-8.
^Court, T. L.; Dove, M. F. A. (1973). "Fluorine compounds of nickel(III)".Journal of the Chemical Society, Dalton Transactions (19): 1995.doi:10.1039/DT9730001995.
^Spokoyny, Alexander M.; Li, Tina C.; Farha, Omar K.; Machan, Charles M.; She, Chunxing; Stern, Charlotte L.; Marks, Tobin J.; Hupp, Joseph T.; Mirkin, Chad A. (June 28, 2010). "Electronic Tuning of Nickel-Based Bis(dicarbollide) Redox Shuttles in Dye-Sensitized Solar Cells".Angew. Chem. Int. Ed.49 (31):5339–5343.doi:10.1002/anie.201002181.PMID20586090.
^Hawthorne, M. Frederick (1967). "(3)-1,2-Dicarbollyl Complexes of Nickel(III) and Nickel(IV)".Journal of the American Chemical Society.89 (2):470–471.Bibcode:1967JAChS..89..470W.doi:10.1021/ja00978a065.
^Baucom, E. I.; Drago, R. S. (1971). "Nickel(II) and nickel(IV) complexes of 2,6-diacetylpyridine dioxime".Journal of the American Chemical Society.93 (24):6469–6475.Bibcode:1971JAChS..93.6469B.doi:10.1021/ja00753a022.
^McLean, Lianne; Yewchuk, Lila; Israel, David M.; Prendiville, Julie S. (January 2011). "Acute Onset of Generalized Pruritic Rash in a Toddler".Pediatric Dermatology.28 (1):53–54.doi:10.1111/j.1525-1470.2010.01367.x.PMID21276052.From 1968 to 1999, Canadian quarters and dimes were minted from 99.9% nickel and nickels from 25 to 99.9% nickel
^Kelly, T. D.; Matos, G. R."Nickel Statistics"(PDF). U.S. Geological Survey.Archived(PDF) from the original on August 12, 2014. RetrievedAugust 11, 2014.
^"Nickel"(PDF).U.S. Geological Survey, Mineral Commodity Summaries. January 2013.Archived(PDF) from the original on May 9, 2013. RetrievedSeptember 20, 2013.
^Gazley, Michael F.; Tay, Stephie; Aldrich, Sean."Polymetallic Nodules".Research Gate. New Zealand Minerals Forum. RetrievedJanuary 27, 2021.
^Mero, J. L. (January 1, 1977). "Chapter 11 Economic Aspects of Nodule Mining".Marine Manganese Deposits. Elsevier Oceanography Series. Vol. 15. pp. 327–355.doi:10.1016/S0422-9894(08)71025-0.ISBN9780444415240.
^International Seabed Authority."Strategic Plan 2019-2023"(PDF).isa.org. International Seabed Authority. Archived fromthe original(PDF) on April 12, 2022. RetrievedJanuary 27, 2021.
^"The Nickel Mountain Project"(PDF).Ore Bin.15 (10):59–66. 1953. Archived from the original on February 12, 2012. RetrievedMay 7, 2015.
^Crundwell, Frank K.; Moats, Michael S.; Ramachandran, Venkoba; Robinson, Timothy G.; Davenport, William G. (2011). "Platinum-Group Metals, Production, Use and Extraction Costs".Extractive Metallurgy of Nickel, Cobalt and Platinum Group Metals. pp. 395–409.doi:10.1016/B978-0-08-096809-4.10031-0.ISBN978-0-08-096809-4.
^Angara, Raghavendra (2009).High Frequency High Amplitude Magnetic Field Driving System for Magnetostrictive Actuators. Umi Dissertation Publishing. p. 5.ISBN9781109187533.
^Cheburaeva, R. F.; Chaporova, I. N.; Krasina, T. I. (1992). "Structure and properties of tungsten carbide hard alloys with an alloyed nickel binder".Soviet Powder Metallurgy and Metal Ceramics.31 (5):423–425.doi:10.1007/BF00796252.
^abcAstrid Sigel; Helmut Sigel; Roland K. O. Sigel, eds. (2008).Nickel and Its Surprising Impact in Nature. Metal Ions in Life Sciences. Vol. 2. Wiley.ISBN978-0-470-01671-8.
^abcSydor, Andrew; Zamble, Deborah (2013). "Nickel Metallomics: General Themes Guiding Nickel Homeostasis". In Banci, Lucia (ed.).Metallomics and the Cell. Metal Ions in Life Sciences. Vol. 12. Dordrecht: Springer. pp. 375–416.doi:10.1007/978-94-007-5561-1_11.ISBN978-94-007-5561-1.PMID23595678.
^Stephen W., Ragdale (2014). "Biochemistry of Methyl-Coenzyme M Reductase: The Nickel Metalloenzyme that Catalyzes the Final Step in Synthesis and the First Step in Anaerobic Oxidation of the Greenhouse Gas Methane". In Peter M.H. Kroneck; Martha E. Sosa Torres (eds.).The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment. Metal Ions in Life Sciences. Vol. 14. Springer. pp. 125–145.doi:10.1007/978-94-017-9269-1_6.ISBN978-94-017-9268-4.PMID25416393.
^Wang, Vincent C.-C.; Ragsdale, Stephen W.; Armstrong, Fraser A. (2014). "Investigations of the Efficient Electrocatalytic Interconversions of Carbon Dioxide and Carbon Monoxide by Nickel-Containing Carbon Monoxide Dehydrogenases". In Peter M.H. Kroneck; Martha E. Sosa Torres (eds.).The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment. Metal Ions in Life Sciences. Vol. 14. Springer. pp. 71–97.doi:10.1007/978-94-017-9269-1_4.ISBN978-94-017-9268-4.PMC4261625.PMID25416391.
^Szilagyi, R. K.; Bryngelson, P. A.; Maroney, M. J.; Hedman, B.; et al. (2004). "S K-Edge X-ray Absorption Spectroscopic Investigation of the Ni-Containing Superoxide Dismutase Active Site: New Structural Insight into the Mechanism".Journal of the American Chemical Society.126 (10):3018–3019.Bibcode:2004JAChS.126.3018S.doi:10.1021/ja039106v.PMID15012109.
^Aronsson A-C; Marmstål E; Mannervik B (1978). "Glyoxalase I, a zinc metalloenzyme of mammals and yeast".Biochemical and Biophysical Research Communications.81 (4):1235–1240.doi:10.1016/0006-291X(78)91268-8.PMID352355.
^Saint-Jean AP; Phillips KR; Creighton DJ; Stone MJ (1998). "Active monomeric and dimeric forms of Pseudomonas putida glyoxalase I: evidence for 3D domain swapping".Biochemistry.37 (29):10345–10353.doi:10.1021/bi980868q.PMID9671502.
^Vander Jagt DL (1989). "Unknown chapter title". In D Dolphin; R Poulson; O Avramovic (eds.).Coenzymes and Cofactors VIII: Glutathione Part A. New York: John Wiley and Sons.
^Zambelli, Barbara; Ciurli, Stefano (2013). "Nickel and Human Health". In Astrid Sigel; Helmut Sigel; Roland K. O. Sigel (eds.).Interrelations between Essential Metal Ions and Human Diseases. Metal Ions in Life Sciences. Vol. 13. Springer. pp. 321–357.doi:10.1007/978-94-007-7500-8_10.ISBN978-94-007-7499-5.PMID24470096.
^"Nickel 203904". Sigma Aldrich. Archived from the original on January 26, 2020. RetrievedJanuary 26, 2020.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
^Butticè, Claudio (2015). "Nickel Compounds". In Colditz, Graham A. (ed.).The SAGE Encyclopedia of Cancer and Society (Second ed.). Thousand Oaks: SAGE Publications, Inc. pp. 828–831.ISBN9781483345734.
^abRegulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on Classification, Labelling and Packaging of Substances and Mixtures, Amending and Repealing Directives 67/548/EEC and 1999/45/EC and amending Regulation (EC) No 1907/2006 [OJ L 353, 31.12.2008, p. 1].Annex VIArchived March 14, 2019, at theWayback Machine. Accessed July 13, 2017.
^abNational Toxicology Program. (2016)."Report on Carcinogens"Archived September 20, 2017, at theWayback Machine, 14th ed. Research Triangle Park, NC: U.S. Department of Health and Human Services, Public Health Service.
^abNational Toxicology Program (1996). "NTP Toxicology and Carcinogenesis Studies of Nickel Subsulfide (CAS No. 12035-72-2) in F344 Rats and B6C3F1 Mice (Inhalation Studies)".National Toxicology Program Technical Report Series.453:1–365.PMID12594522.
^National Toxicology Program (1996). "NTP Toxicology and Carcinogenesis Studies of Nickel Oxide (CAS No. 1313-99-1) in F344 Rats and B6C3F1 Mice (Inhalation Studies)".National Toxicology Program Technical Report Series.451:1–381.PMID12594524.
^National Toxicology Program (1996). "NTP Toxicology and Carcinogenesis Studies of Nickel Sulfate Hexahydrate (CAS No. 10101-97-0) in F344 Rats and B6C3F1 Mice (Inhalation Studies)".National Toxicology Program Technical Report Series.454:1–380.PMID12587012.
^Springborn Laboratories Inc. (2000). "An Oral (Gavage) Two-generation Reproduction Toxicity Study in Sprague-Dawley Rats with Nickel Sulfate Hexahydrate." Final Report. Springborn Laboratories Inc., Spencerville. SLI Study No. 3472.4.
^Vaktskjold, A; Talykova, L. V; Chashchin, V. P; Odland, J. O; Nieboer, E (2008). "Maternal nickel exposure and congenital musculoskeletal defects".American Journal of Industrial Medicine.51 (11):825–33.doi:10.1002/ajim.20609.PMID18655106.
_NIST_ASD_emission_spectrum.png)
_ion.png)
_complexes_in_aqueous_solution.jpg)
-sulfate-hexahydrate-sample.jpg)
