View source for Chemistry:Nickel

{{pp-semi-indef}}
{{Infobox nickel}}

'''Nickel''' is a [[Chemistry:Chemical element|chemical element]]; it has [[Chemistry:Chemical symbol|symbol]] '''Ni''' and [[Physics:Atomic number|atomic number]] 28. It is a silvery-white lustrous [[Chemistry:Metal|metal]] with a slight golden tinge. Nickel is a hard and [[Physics:Ductility|ductile]] [[Chemistry:Transition metal|transition metal]]. Pure nickel is chemically reactive, but large pieces are slow to react with air under [[Standard conditions for temperature and pressure|standard conditions]] because a [[Engineering:Passivation|passivation layer]] of [[Chemistry:Nickel(II) oxide|nickel oxide]] forms on the surface that prevents further corrosion. Even so, pure [[Chemistry:Native metal|native]] nickel is found in Earth's crust only in tiny amounts, usually in [[Chemistry:Ultramafic rock|ultramafic rock]]s,<ref>{{cite book |editor=Anthony, John W. |editor2=Bideaux, Richard A. |editor3=Bladh, Kenneth W. |editor4=Nichols, Monte C. |title= Handbook of Mineralogy|publisher= Mineralogical Society of America|place= Chantilly, Virginia, US|chapter-url=http://www.handbookofmineralogy.org/pdfs/nickel.pdf|chapter=Nickel|isbn=978-0962209703 |volume=I|year=1990}}</ref><ref>{{cite web|url=http://www.mindat.org/min-2895.html|title=Nickel: Nickel mineral information and data|website=Mindat.org|access-date=2016-03-02|archive-url=https://web.archive.org/web/20160303184003/http://www.mindat.org/min-2895.html|archive-date=March 3, 2016|url-status=live}}</ref> and in the interiors of larger [[Astronomy:Iron meteorite|nickel–iron meteorites]] that were not exposed to oxygen when outside Earth's atmosphere.

[[Chemistry:Meteoric iron|Meteoric nickel]] is found in combination with [[Chemistry:Iron|iron]], a reflection of the origin of those elements as major end products of [[Physics:Supernova nucleosynthesis|supernova nucleosynthesis]]. An iron–nickel mixture is thought to compose [[Earth:Earth's outer core|Earth's outer]] and [[Earth:Earth's inner core|inner cores]].<ref>{{cite journal | first1=Lars|last1=Stixrude | first2=Evgeny|last2=Waserman |first3=Ronald |last3=Cohen | title = Composition and temperature of Earth's inner core | journal = Journal of Geophysical Research | volume = 102 | issue = B11 | pages = 24729–24740 |date=November 1997 | doi = 10.1029/97JB02125 | bibcode=1997JGR...10224729S| doi-access= }}</ref>

Use of nickel (as natural [[Chemistry:Meteoric iron|meteoric]] nickel–iron alloy) has been traced as far back as 3500&nbsp;BCE. Nickel was first isolated and classified as an element in 1751 by [[Biography:Axel Fredrik Cronstedt|Axel Fredrik Cronstedt]], who initially mistook the [[Earth:Ore|ore]] for a [[Chemistry:Copper|copper]] [[Earth:Mineral|mineral]], in the cobalt mines of Los, Hälsingland, Sweden. The element's name comes from a mischievous sprite of German miner mythology, Nickel (similar to [[Unsolved:Devil in Christianity#Christian tradition|Old Nick]]). Nickel minerals were green, like copper ores, and were known as kupfernickel – Nickel's copper – because they produced no copper. An economically important source of nickel is the [[Chemistry:Iron|iron]] ore [[Chemistry:Limonite|limonite]], which is often 1–2% nickel. Other important nickel ore minerals include [[Chemistry:Pentlandite|pentlandite]] and a mix of Ni-rich natural silicates known as [[Chemistry:Garnierite|garnierite]]. Major production sites include the [[Earth:Sudbury Basin|Sudbury region]], Canada (which is thought to be of [[Astronomy:Meteorite|meteoric]] origin), [[Earth:New Caledonia|New Caledonia]] in the [[Earth:Pacific Ocean|Pacific]], and Norilsk, Russia.

Nickel is one of four elements (the others are [[Chemistry:Iron|iron]], [[Chemistry:Cobalt|cobalt]], and [[Chemistry:Gadolinium|gadolinium]])<ref name="CoeySkumryev1999">{{cite journal|last1=Coey| first1=J. M. D.| last2=Skumryev| first2=V.|last3=Gallagher|first3=K.|journal=Nature |volume=401| issue=6748| year=1999| pages=35–36|doi=10.1038/43363 | title = Rare-earth metals: Is gadolinium really ferromagnetic?|bibcode=1999Natur.401...35C| s2cid=4383791}}</ref> that are [[Physics:Ferromagnetic|ferromagnetic]] at about room temperature. [[Physics:Alnico|Alnico]] permanent magnets based partly on nickel are of intermediate strength between iron-based permanent magnets and [[Physics:Rare-earth magnet|rare-earth magnet]]s. The metal is used chiefly in [[Chemistry:Alloy|alloy]]s and corrosion-resistant plating. About 68% of world production is used in [[Chemistry:Stainless steel|stainless 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,<ref name="Nickel Use In Society">{{Cite web |title=Nickel in Batteries |url=https://nickelinstitute.org/en/about-nickel-and-its-applications/nickel-in-batteries/ |url-status=live |archive-url=https://web.archive.org/web/20170921000402/https://www.nickelinstitute.org/NickelUseInSociety/AboutNickel/FirstAndEndUsesofNickel.aspx |archive-date=September 21, 2017 |website=Nickel Institute}}</ref> including those in [[Engineering:Electric vehicle|electric vehicle]]s (EVs).<ref>{{Cite web|last=Treadgold|first=Tim|title=Gold Is Hot But Nickel Is Hotter As Demand Grows For Batteries In Electric Vehicles|url=https://www.forbes.com/sites/timtreadgold/2019/08/11/gold-is-hot-but-nickel-is-hotter-as-demand-grows-for-batteries-in-electric-vehicles/|access-date=2020-10-14|website=Forbes}}</ref> Nickel is widely used in coins, though nickel-plated objects sometimes provoke [[Medicine:Nickel allergy|nickel allergy]]. As a compound, nickel has a number of niche chemical manufacturing uses, such as a [[Chemistry:Raney nickel|catalyst for hydrogenation]], [[Physics:Cathode|cathode]]s for rechargeable batteries, pigments and metal surface treatments.<ref>{{Cite web |title=Nickel Compounds |url=https://nickelinstitute.org/media/2298/ni-compounds-2015-v12-final.pdf |url-status=live |archive-url=https://web.archive.org/web/20180831002419/https://nickelinstitute.org/~/media/Files/MediaCenter/NiCompounds/NI%20Compounds%202015%20v12%20FINAL.ashx?la=en |archive-date=2018-08-31 |website=Nickel Institute}}</ref> Nickel is an essential nutrient for some microorganisms and plants that have [[Biology:Enzymes|enzymes]] with nickel as an [[Biology:Active site|active site]].<ref>{{Cite journal|last1=Mulrooney|first1=Scott B.|last2=Hausinger|first2=Robert P.|date=2003-06-01|title=Nickel uptake and utilization by microorganisms|journal=FEMS Microbiology Reviews|volume=27|issue=2–3|pages=239–261|doi=10.1016/S0168-6445(03)00042-1|pmid=12829270|issn=0168-6445|doi-access=free}}</ref>

==Properties==

===Atomic and physical properties===
[[File:Ni@CNT2.jpg|thumb|left|[[Engineering:Transmission electron microscopy|Electron micrograph]] of a Ni nanocrystal inside a single wall carbon nanotube; scale bar 5&nbsp;nm<ref>{{cite journal|doi=10.1038/srep15033|pmid=26459370|pmc=4602218|title=Nickel clusters embedded in carbon nanotubes as high performance magnets|journal=Scientific Reports|volume=5|page=15033|date=2015|display-authors=4|last1=Shiozawa|first1=Hidetsugu|last2=Briones-Leon|first2=Antonio|last3=Domanov|first3=Oleg|last4=Zechner|first4=Georg|last5=Sato|first5=Yuta|last6=Suenaga|first6=Kazu|last7=Saito|first7=Takeshi|last8=Eisterer|first8=Michael|last9=Weschke|first9=Eugen|last10=Lang|first10=Wolfgang|last11=Peterlik|first11=Herwig|last12=Pichler|first12=Thomas|bibcode=2015NatSR...515033S}}</ref>]]
Nickel is a silvery-white metal with a slight golden tinge that takes a high polish. It is one of only four elements that are [[Physics:Ferromagnetism|ferromagnetic]] at or near room temperature; the others are iron, [[Chemistry:Cobalt|cobalt]] and [[Chemistry:Gadolinium|gadolinium]]. Its [[Physics:Curie temperature|Curie temperature]] is {{convert|355|°C|°F|}}, meaning that bulk nickel is non-magnetic above this temperature.<ref>{{cite book |author=Kittel, Charles|title=[[Physics:Introduction to Solid State Physics|Introduction to Solid State Physics]] |publisher=Wiley |date=1996 |page=449 |isbn=978-0-471-14286-7}}</ref><ref name="CoeySkumryev1999" /> The unit cell of nickel is a [[Cubic crystal system|face-centered cube]]; it has lattice parameter of 0.352&nbsp;nm, giving an [[Physics:Atomic radius|atomic radius]] of 0.124&nbsp;nm. This crystal structure is stable to pressures of at least 70&nbsp;GPa. Nickel is hard, malleable and [[Physics:Ductility|ductile]], and has a relatively high [[Physics:Electrical resistivity and conductivity|electrical]] and [[Physics:Thermal conductivity|thermal conductivity]] for transition metals.<ref name="crc" /> The high [[Engineering:Compressive strength|compressive strength]] of 34 GPa, predicted for ideal crystals, is never obtained in the real bulk material due to formation and movement of dislocations. However, it has been reached in Ni [[Physics:Nanoparticle|nanoparticle]]s.<ref>{{cite journal|doi=10.1038/s41467-018-06575-6|pmid=30291239|pmc=6173750|title=Nickel nanoparticles set a new record of strength|journal=Nature Communications|volume=9|issue=1|pages=4102|year=2018|last1=Sharma|first1=A.|last2=Hickman|first2=J.|last3=Gazit|first3=N.|last4=Rabkin|first4=E.|last5=Mishin|first5=Y.|bibcode=2018NatCo...9.4102S}}</ref>

====Electron configuration dispute====
Nickel has two atomic [[Physics:Electron configuration|electron configuration]]s, [Ar] 3d{{sup|8}} 4s{{sup|2}} and [Ar] 3d{{sup|9}} 4s{{sup|1}}, which are very close in energy; [Ar] denotes the complete [[Chemistry:Argon|argon]] core structure. There is some disagreement on which configuration has the lower energy.<ref name="Scerri" /> Chemistry textbooks quote nickel's electron configuration as [Ar] 4s{{sup|2}} 3d{{sup|8}},<ref>Miessler, G.L. and Tarr, D.A. (1999) ''Inorganic Chemistry'' 2nd ed., Prentice–Hall. p. 38. {{ISBN|0138418918}}.</ref> also written [Ar] 3d{{sup|8}} 4s{{sup|2}}.<ref>Petrucci, R.H. et al. (2002) ''General Chemistry'' 8th ed., Prentice–Hall. p. 950. {{ISBN|0130143294}}.</ref> This configuration agrees with the Madelung 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 3d{{sup|8}} 4s{{sup|2}} energy level, specifically the 3d{{sup|8}}({{sup|3}}F) 4s{{sup|2}} {{sup|3}}F, ''J''&nbsp;=&nbsp;4 level.<ref name="JPCRD">{{cite web |last1=Corliss |first1=Charles |last2=Sugar |first2=Jack |title=Energy levels of nickel, Ni I through Ni XXVIII |page=200 |url=https://srd.nist.gov/jpcrdreprint/1.555638.pdf |publisher=Journal of Physical and Chemical Reference Data |access-date=5 March 2023 |date=15 October 2009 |quote=In this table Ni I = neutral Ni atom, Ni II = Ni+ etc.}}</ref><ref name="NIST">[http://physics.nist.gov/PhysRefData/ASD/levels_form.html NIST Atomic Spectrum Database] {{Webarchive|url=https://web.archive.org/web/20110320190125/http://physics.nist.gov/PhysRefData/ASD/levels_form.html |date=March 20, 2011 }} To read the nickel atom levels, type "Ni 0" or "Ni I" in the Spectrum box and click on Retrieve data.</ref>

However, each of these two configurations splits into several energy levels due to [[Physics:Fine structure|fine structure]],<ref name="JPCRD"/><ref name="NIST" /> and the two sets of energy levels overlap. The average energy of states with [Ar] 3d{{sup|9}} 4s{{sup|1}} is actually lower than the average energy of states with [Ar] 3d{{sup|8}} 4s{{sup|2}}. Therefore, the research literature on atomic calculations quotes the ground state configuration as [Ar] 3d{{sup|9}} 4s{{sup|1}}.<ref name="Scerri">{{cite book |url=https://archive.org/details/periodictableits0000scer |url-access=registration |pages=[https://archive.org/details/periodictableits0000scer/page/239 239]–240 |title=The periodic table: its story and its significance |author=Scerri, Eric R. |publisher=Oxford University Press|date=2007 |isbn=978-0-19-530573-9}}</ref>

===Isotopes===
{{Main|Physics:Isotopes of nickel}}
The isotopes of nickel range in [[Physics:Atomic weight|atomic weight]] from 48&nbsp;u ({{chem|48|Ni}}) to 82&nbsp;u ({{chem|82|Ni}}).{{NUBASE2020|ref}}

Natural nickel is composed of five stable [[Physics:Isotope|isotope]]s, {{chem|58|Ni}}, {{chem|60|Ni}}, {{chem|61|Ni}}, {{chem|62|Ni}} and {{chem|64|Ni}}, of which {{chem|58|Ni}} is the most abundant (68.077% [[Chemistry:Natural abundance|natural abundance]]).{{NUBASE2020|ref}}

[[Physics:Nickel-62|Nickel-62]] has the highest [[Physics:Nuclear binding energy|binding energy]] per nucleon of any [[Physics:Nuclide|nuclide]]: 8.7946&nbsp;MeV/nucleon.<ref>{{cite journal|url = http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin2.html#c1|title = The Most Tightly Bound Nuclei|journal = American Journal of Physics|volume = 57|issue = 6|pages = 552|access-date = November 19, 2008|archive-url = https://web.archive.org/web/20110514050922/http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin2.html#c1|archive-date = May 14, 2011|url-status = live|bibcode = 1989AmJPh..57..552S|last1 = Shurtleff|first1 = Richard|last2 = Derringh|first2 = Edward|year = 1989|doi = 10.1119/1.15970}}</ref><ref>{{Cite web|title=Nuclear synthesis|url=http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/nucsyn.html|access-date=2020-10-15|website=hyperphysics.phy-astr.gsu.edu}}</ref> Its binding energy is greater than both [[Physics:Iron-56|{{chem|56|Fe}}]] and [[Physics:Iron-58|{{chem|58|Fe}}]], more abundant nuclides often incorrectly cited as having the highest binding energy.<ref name="aip1995">{{cite journal | doi = 10.1119/1.17828 | title=The atomic nuclide with the highest mean binding energy | journal=American Journal of Physics | date=1995 | volume=63 | issue=7 | page=653 | first=M. P. | last=Fewell| bibcode=1995AmJPh..63..653F }}</ref> Though this would seem to predict nickel as the most abundant heavy element in the universe, the high rate of [[Physics:Photodisintegration|photodisintegration]] of nickel in stellar interiors causes iron to be by far the most abundant.<ref name="aip1995" />

Nickel-60 is the daughter product of the [[Chemistry:Extinct radionuclide|extinct radionuclide]] [[Physics:Iron-60|{{chem|60|Fe}}]] (half-life 2.6&nbsp;million years). Due to the long half-life of {{chem|60|Fe}}, its persistence in materials in the [[Astronomy:Solar System|Solar System]] may generate observable variations in the isotopic composition of {{chem|60|Ni}}. Therefore, the abundance of {{chem|60|Ni}} in extraterrestrial material may give insight into the origin of the Solar System and its early history.<ref>{{cite web |last1=Caldwell |first1=Eric |title=Resources on Isotopes |url=https://wwwrcamnl.wr.usgs.gov/isoig/period/ni_iig.html |publisher=United States Geological Survey |access-date=20 May 2022}}</ref>

At least 26 nickel radioisotopes have been characterized; the most stable are {{chem|59|Ni}} with [[Physics:Half-life|half-life]] 76,000 years, {{chem|63|Ni}} (100 years), and {{chem|56||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 one meta state.{{NUBASE2020|ref}}

Radioactive nickel-56 is produced by the silicon burning process and later set free in large amounts in [[Astronomy:Type Ia supernova|type Ia]] [[Astronomy:Supernova|supernova]]e. The shape of the [[Astronomy:Light curve|light curve]] of these supernovae at intermediate to late-times corresponds to the decay via [[Physics:Electron capture|electron capture]] of {{chem|56|Ni}} to [[Chemistry:Cobalt|cobalt]]-56 and ultimately to iron-56.<ref name="Nucleos">{{cite book |title = Nucleosynthesis and chemical evolution of galaxies|chapter-url = https://archive.org/details/nucleosynthesisc0000page|chapter-url-access = registration| isbn= 978-0-521-55958-4| pages = [https://archive.org/details/nucleosynthesisc0000page/page/154 154–160]| chapter = Further burning stages: evolution of massive stars| first = Bernard Ephraim Julius|last = Pagel| date= 1997| publisher=Cambridge University Press }}</ref> Nickel-59 is a long-lived [[Physics:Cosmogenic nuclide|cosmogenic]] [[Physics:Radionuclide|radionuclide]]; half-life 76,000 years. {{chem|59|Ni}} has found many applications in isotope geology. {{chem|59|Ni}} has been used to date the terrestrial age of [[Astronomy:Meteorite|meteorite]]s and to determine abundances of extraterrestrial dust in ice and [[Earth:Sediment|sediment]]. The half-life of nickel-78 was recently measured at 110 milliseconds, and is believed an important isotope in [[Physics:Supernova nucleosynthesis|supernova nucleosynthesis]] of elements heavier than iron.<ref>{{cite web|url = http://www.skyandtelescope.com/news/3310246.html?page=1&c=y|title = Atom Smashers Shed Light on Supernovae, Big Bang|date = April 22, 2005|first = Davide|last = Castelvecchi|access-date = November 19, 2008|archive-url = https://archive.today/20120723105754/http://www.skyandtelescope.com/news/3310246.html?page=1&c=y|archive-date = July 23, 2012|url-status = dead}}</ref> {{sup|48}}Ni, discovered in 1999, is the most proton-rich heavy element isotope known. With 28 [[Physics:Proton|proton]]s and 20 [[Physics:Neutron|neutron]]s, {{sup|48}}Ni is "doubly magic", as is {{sup|78}}Ni with 28 protons and 50 neutrons. Both are therefore unusually stable for nuclei with so large a [[Physics:Neutron–proton ratio|proton–neutron imbalance]].{{NUBASE2020|ref}}<ref>{{cite magazine|last = W|first = P.|title = Twice-magic metal makes its debut – isotope of nickel|magazine=Science News|date = October 23, 1999|url = http://www.findarticles.com/p/articles/mi_m1200/is_17_156/ai_57799535|archive-url = https://archive.today/20120524134125/http://www.findarticles.com/p/articles/mi_m1200/is_17_156/ai_57799535|url-status = dead|archive-date = May 24, 2012|access-date = September 29, 2006}}</ref>

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.<ref>{{cite journal | last1=Carboneau | first1=M. L.| last2=Adams | first2=J. P.| title=Nickel-63| journal=National Low-Level Waste Management Program Radionuclide Report Series| volume=10 | date=1995 | doi=10.2172/31669 | url=https://digital.library.unt.edu/ark:/67531/metadc674188/}}</ref>

===Occurrence===
[[File:Widmanstatten hand.jpg|thumb|left|[[Earth:Widmanstätten pattern|Widmanstätten pattern]] showing the two forms of nickel–iron, kamacite and taenite, in an octahedrite meteorite]]
On Earth, nickel occurs most often in combination with [[Chemistry:Sulfur|sulfur]] and iron in [[Chemistry:Pentlandite|pentlandite]], with [[Chemistry:Sulfur|sulfur]] in [[Chemistry:Millerite|millerite]], with [[Chemistry:Arsenic|arsenic]] in the mineral [[Chemistry:Nickeline|nickeline]], and with arsenic and [[Chemistry:Sulfur|sulfur]] in nickel [[Chemistry:Galena|galena]].<ref>[http://www.npi.gov.au/substances/nickel/index.html National Pollutant Inventory – Nickel and compounds Fact Sheet] {{Webarchive|url=https://web.archive.org/web/20111208083730/http://www.npi.gov.au/substances/nickel/index.html |date=December 8, 2011 }}. Npi.gov.au. Retrieved on January 9, 2012.</ref> Nickel is commonly found in [[Astronomy:Iron meteorite|iron meteorite]]s as the alloys [[Chemistry:Kamacite|kamacite]] and [[Chemistry:Taenite|taenite]]. Nickel in meteorites was first detected in 1799 by Joseph-Louis Proust, a French chemist who then worked in Spain. Proust analyzed samples of the meteorite from Campo 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.<ref>{{Cite book|title=Construyendo la Tabla Periódica|last=Calvo|first=Miguel|publisher=Prames|year=2019|isbn=978-84-8321-908-9|location=Zaragoza, Spain|pages=118}}</ref>

The bulk of nickel is mined from two types of [[Earth:Ore|ore]] deposits. The first is [[Earth:Laterite|laterite]], where the principal ore mineral mixtures are nickeliferous [[Chemistry:Limonite|limonite]], (Fe,Ni)O(OH), and [[Chemistry:Garnierite|garnierite]] (a mixture of various hydrous nickel and nickel-rich silicates). The second is magmatic [[Chemistry:Sulfide|sulfide]] deposits, where the principal ore mineral is [[Chemistry:Pentlandite|pentlandite]]: {{chem2|(Ni,Fe)9S8}}.<ref name="Mudd 2010 pp. 9–26">{{cite journal | last=Mudd | first=Gavin M. | title=Global trends and environmental issues in nickel mining: Sulfides versus laterites | journal=Ore Geology Reviews | publisher=Elsevier BV | volume=38 | issue=1–2 | year=2010 | issn=0169-1368 | doi=10.1016/j.oregeorev.2010.05.003 | pages=9–26| bibcode=2010OGRv...38....9M }}</ref>

Indonesia and {{wipe|Australia}} have the biggest estimated reserves, at 43.6% of world total.<ref>{{Cite web|title=Nickel reserves worldwide by country 2020|url=https://www.statista.com/statistics/273634/nickel-reserves-worldwide-by-country/|access-date=2021-03-29|website=Statista}}</ref>

Identified land-based resources throughout the world averaging 1% nickel or greater comprise at least 130&nbsp;million tons of nickel (about the double of known reserves). About 60% is in laterites and 40% in sulfide deposits.<ref name="USGSCS2019">{{cite web|first = Peter H.|last = Kuck|publisher = United States Geological Survey|title = Mineral Commodity Summaries 2019: Nickel|url = https://minerals.usgs.gov/minerals/pubs/commodity/nickel/mcs-2019-nicke.pdf|access-date = March 18, 2019|archive-url = https://web.archive.org/web/20190421125020/https://minerals.usgs.gov/minerals/pubs/commodity/nickel/mcs-2019-nicke.pdf|archive-date = April 21, 2019|url-status = live}}</ref>

On [[Physics:Geophysics|geophysical]] evidence, most of the nickel on Earth is believed to be in Earth's [[Physics:Outer core|outer]] and [[Earth:Inner core|inner core]]s. [[Chemistry:Kamacite|Kamacite]] and [[Chemistry:Taenite|taenite]] are naturally occurring [[Chemistry:Alloy|alloy]]s of iron and nickel. For kamacite, the alloy is usually in the proportion of 90:10 to 95:5, though impurities (such as [[Chemistry:Cobalt|cobalt]] or [[Chemistry:Carbon|carbon]]) may be present. Taenite is 20% to 65% nickel. Kamacite and taenite are also found in nickel iron meteorites.<ref>{{cite journal|title = Trace element partitioning between taenite and kamacite – Relationship to the cooling rates of iron meteorites|last1= Rasmussen|first1=K. L.|last2= Malvin|first2=D. J.|last3= Wasson|first3=J. T.|journal=Meteoritics |volume= 23|date = 1988|pages = a107–112 |bibcode= 1988Metic..23..107R|doi = 10.1111/j.1945-5100.1988.tb00905.x|issue = 2}}</ref>

==Compounds==
{{Main|Chemistry:Nickel compounds}}
The most common [[Chemistry:Oxidation state|oxidation state]] of nickel is +2, but compounds of {{chem2|Ni^{0}|}}, {{chem2|Ni+}}, and {{chem2|Ni(3+)}} are well known, and the exotic oxidation states {{chem2|Ni(2−)}} and {{chem2|Ni−}} have been produced and studied.<ref name="Greenwood">{{Greenwood&Earnshaw2nd}}</ref>{{clear}}

===Nickel(0)===
[[File:Nickel-tetracarbonyl-2D.png|thumb|upright=0.7|alt=A nickel atom with four single bonds to carbonyl (carbon triple-bonded to oxygen; bonds via the carbon) groups that are laid out tetrahedrally around it|Tetracarbonyl nickel]]
[[Chemistry:Nickel tetracarbonyl|Nickel tetracarbonyl]] {{chem2|(Ni(CO)4}}), discovered by Ludwig Mond,<ref name="MondNa">{{cite journal|date = 1898|journal=Nature| doi = 10.1038/059063a0|title = The Extraction of Nickel from its Ores by the Mond Process|volume = 59|pages = 63–64|issue=1516|bibcode = 1898Natur..59...63. |doi-access = free}}</ref> is a volatile, highly toxic liquid at room temperature. On heating, the complex decomposes back to nickel and carbon monoxide:
:{{chem2|Ni(CO)4 ⇌ Ni + 4 CO}}
This behavior is exploited in the [[Chemistry:Mond process|Mond process]] for purifying nickel, as described above. The related nickel(0) complex [[Chemistry:Bis(cyclooctadiene)nickel(0)|bis(cyclooctadiene)nickel(0)]] is a useful catalyst in [[Chemistry:Organonickel chemistry|organonickel chemistry]] because the [[Chemistry:1,5-Cyclooctadiene|cyclooctadiene]] (or ''cod'') ligands are easily displaced.{{clear}}

=== Nickel(I) ===
[[File:Structure_of_hexacyanodinickelate(I)_ion.png|thumb|Structure of {{chem2|[Ni2(CN)6](4-)}} ion<ref name="InorgChemH" />]]
Nickel(I) complexes are uncommon, but one example is the tetrahedral complex {{chem2|NiBr(PPh3)3}}. Many nickel(I) complexes have Ni–Ni bonding, such as the dark red diamagnetic {{chem2|K4[Ni2(CN)6]}} prepared by reduction of {{chem2|K2[Ni2(CN)6]}} with [[Chemistry:Sodium amalgam|sodium amalgam]]. This compound is oxidized in water, liberating {{chem2|H2}}.<ref name="InorgChemH">{{Housecroft3rd|page=729}}</ref>

It is thought that the nickel(I) oxidation state is important to nickel-containing enzymes, such as [NiFe]-hydrogenase, which catalyzes the reversible reduction of protons to {{chem2|H2}}.<ref name="Housecroft 4th">{{Housecroft4th|page=764}}</ref>{{clear}}

===Nickel(II)===
[[File:Color of various Ni(II) complexes in aqueous solution.jpg|thumb|upright=2.05|Color of various Ni(II) complexes in aqueous solution. From left to right, {{chem2|[Ni(NH3)6](2+)}}, {{chem2|[Ni([[Chemistry:Ethylenediamine|NH2CH2CH2NH2]])](2+)}}, {{chem2|[NiCl4](2-)}}, {{chem2|[Ni(H2O)6](2+)}}]]
[[File:Nickel(II)-sulfate-hexahydrate-sample.jpg|thumb|upright=0.8|alt=A small heap of cyan crystal particles|Crystals of hydrated nickel(II) sulfate]]
Nickel(II) forms compounds with all common anions, including [[Chemistry:Nickel sulfide|sulfide]], [[Chemistry:Nickel sulfate|sulfate]], carbonate, hydroxide, carboxylates, and halides. [[Chemistry:Nickel(II) sulfate|Nickel(II) sulfate]] is produced in large amounts by dissolving nickel metal or oxides in [[Chemistry:Sulfuric acid|sulfuric acid]], forming both a hexa- and heptahydrate<ref name=NiCmpds>Lascelles, Keith; Morgan, Lindsay G.; Nicholls, David and Beyersmann, Detmar (2019) "Nickel Compounds" in ''Ullmann's Encyclopedia of Industrial Chemistry''. Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a17_235.pub3}}</ref> useful for [[Chemistry:Nickel electroplating|electroplating]] nickel. Common salts of nickel, such as chloride, nitrate, and sulfate, dissolve in water to give green solutions of the [[Chemistry:Metal aquo complex|metal aquo complex]] {{chem2|[Ni(H2O)6](2+)}}.<ref>{{Cite web |title=A Review on the Metal Complex of Nickel (Ii) Salicylhydroxamic Acid and its Aniline Adduct |url=https://www.heraldopenaccess.us/openaccess/a-review-on-the-metal-complex-of-nickel-ii-salicylhydroxamic-acid-and-its-aniline-adduct |access-date=2022-07-19 |website=www.heraldopenaccess.us}}</ref>

The four halides form nickel compounds, which are solids with molecules with octahedral Ni centres. [[Chemistry:Nickel(II) chloride|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 in [[Chemistry:Hydrochloric acid|hydrochloric acid]]. It is usually found as the green hexahydrate, whose formula is usually written {{chem2|NiCl2*6H2O}}. When dissolved in water, this salt forms the [[Chemistry:Metal aquo complex|metal aquo complex]] {{chem2|[Ni(H2O)6](2+)}}. Dehydration of {{chem2|NiCl2*6H2O}} gives yellow anhydrous {{chem2|NiCl2}}.<ref>{{Cite web |title=metal - The Reaction Between Nickel and Hydrochloric Acid |url=https://chemistry.stackexchange.com/questions/54895/the-reaction-between-nickel-and-hydrochloric-acid |access-date=2022-07-19 |website=Chemistry Stack Exchange}}</ref>

Some tetracoordinate nickel(II) complexes, e.g. bis(triphenylphosphine)nickel chloride, exist both in tetrahedral and square planar geometries. The tetrahedral complexes are [[Physics:Paramagnetic|paramagnetic]]; the square planar complexes are diamagnetic. 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.<ref name="Greenwood" />

[[Chemistry:Nickelocene|Nickelocene]] is known and has an [[Chemistry:Electron counting|electron count]] of 20. It is much less stable than ferrocene. Many chemical reactions of nickelocene tend to yield 18-electron products.<ref>{{cite book |last1=Miessler |first1=Gary L. |last2=Tarr |first2=Donald A. |title=Inorganic Chemistry |date=1999 |publisher=Prentice-Hall |isbn=0-13-841891-8 |page=456–457 |edition=2nd}}</ref>

===Nickel(III) and (IV)===
[[File:Nickel antimonide.jpg|thumb|upright|Nickel(III) antimonide]]
Many Ni(III) compounds are known. Ni(III) forms simple salts with fluoride<ref name = "Ni(III)F">{{Cite journal | doi = 10.1039/DT9730001995| title = Fluorine compounds of nickel(III)| journal = Journal of the Chemical Society, Dalton Transactions| issue = 19| page = 1995| date = 1973| last1 = Court | first1 = T. L.| last2 = Dove | first2 = M. F. A.}}</ref> or [[Chemistry:Nickel(III) oxide|oxide]] ions. Ni(III) can be stabilized by σ-donor ligands such as [[Chemistry:Thiol|thiol]]s and [[Chemistry:Organophosphine|organophosphine]]s.<ref name="InorgChemH" />

Ni(III) occurs in [[Chemistry:Nickel oxide hydroxide|nickel oxide hydroxide]], which is used as the [[Physics:Cathode|cathode]] in many [[Engineering:Rechargeable battery|rechargeable batteries]], including [[Chemistry:Nickel–cadmium battery|nickel–cadmium]], [[Chemistry:Nickel–iron battery|nickel–iron]], [[Physics:Nickel–hydrogen battery|nickel–hydrogen]], and [[Chemistry:Nickel–metal hydride battery|nickel–metal hydride]], and used by certain manufacturers in [[Engineering:Lithium-ion battery|Li-ion batteries]].<ref>{{cite news|url=http://www.greencarcongress.com/2008/12/imara-corporati.html|title=Imara Corporation Launches; New Li-ion Battery Technology for High-Power Applications|date=December 18, 2008|publisher=Green Car Congress|access-date=January 22, 2009|archive-url=https://web.archive.org/web/20081222102915/http://www.greencarcongress.com/2008/12/imara-corporati.html|archive-date=December 22, 2008|url-status=live}}</ref>

Ni(IV) occurs in the mixed oxide {{chem2|BaNiO3}}. Ni(IV) remains a rare oxidation state and very few compounds are known.<ref>{{cite journal|last1=Spokoyny|first1=Alexander M.|last2=Li|first2=Tina C.|last3=Farha|first3=Omar K.|last4=Machan|first4=Charles M.|last5=She|first5=Chunxing|last6=Stern|first6=Charlotte L.|last7=Marks|first7=Tobin J.|last8=Hupp|first8=Joseph T.|last9=Mirkin|first9=Chad A.|title=Electronic Tuning of Nickel-Based Bis(dicarbollide) Redox Shuttles in Dye-Sensitized Solar Cells|journal=Angew. Chem. Int. Ed.|date=28 June 2010|pages=5339–5343|doi=10.1002/anie.201002181|volume=49|issue=31|pmid=20586090}}</ref><ref>{{cite journal|last1=Hawthorne|first1=M. Frederick|title=(3)-1,2-Dicarbollyl Complexes of Nickel(III) and Nickel(IV)|journal=Journal of the American Chemical Society |date=1967|volume=89|issue=2|pages=470–471|doi=10.1021/ja00978a065}}</ref><ref name="NiIV Science">{{Cite journal | doi = 10.1126/science.aaa4526| pmid = 25766226| title = Design, synthesis, and carbon-heteroatom coupling reactions of organometallic nickel(IV) complexes| journal = Science| volume = 347| issue = 6227| pages = 1218–20| date = 2015| last1 = Camasso | first1 = N. M.| last2 = Sanford | first2 = M. S.| bibcode = 2015Sci...347.1218C| citeseerx = 10.1.1.897.9273| s2cid = 206634533}}</ref><ref name="NiIV dap">{{Cite journal | doi = 10.1021/ja00753a022| title = Nickel(II) and nickel(IV) complexes of 2,6-diacetylpyridine dioxime| journal = Journal of the American Chemical Society| volume = 93| issue = 24| pages = 6469–6475| date = 1971| last1 = Baucom | first1 = E. I. | last2 = Drago | first2 = R. S.}}</ref>

==History==
Because nickel ores are easily mistaken for ores of silver and copper, understanding of this metal and of its use is relatively recent. But unintentional use of nickel is ancient, and can be traced back as far as 3500&nbsp;BCE. [[Chemistry:Bronze|Bronze]]s from what is now Syria have been found to contain as much as 2% nickel.<ref>{{cite book|title = Nickel and Its Alloys|publisher = National Bureau of Standards|first = Samuel J.|last = Rosenberg|url = http://handle.dtic.mil/100.2/ADA381960|archive-url = https://web.archive.org/web/20120523193126/http://handle.dtic.mil/100.2/ADA381960|url-status = dead|archive-date = May 23, 2012|date = 1968}}</ref> Some ancient Chinese manuscripts suggest that "white copper" ([[Chemistry:Cupronickel|cupronickel]], known as ''baitong'') was used there in 1700–1400&nbsp;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.<ref name="McNeil">{{cite book|title = An Encyclopaedia of the History of Technology|chapter = The Emergence of Nickel|first = Ian|last = McNeil|publisher = Taylor & Francis|date = 1990|isbn = 978-0-415-01306-2|pages = [https://archive.org/details/encyclopaediaofh00mcne/page/96 96–100]|chapter-url = https://archive.org/details/encyclopaediaofh00mcne/page/96}}</ref> Coins of nickel-copper alloy were minted by Bactrian kings Agathocles, Euthydemus II, and Pantaleon in the 2nd century BCE, possibly out of the Chinese cupronickel.<ref>[[Biography:Joseph Needham|Needham, Joseph]]; Wang, Ling; Lu, Gwei-Djen; Tsien, Tsuen-hsuin; Kuhn, Dieter and Golas, Peter J. (1974) [https://books.google.com/books?id=BYixSmXUCuMC&pg=PA237 ''Science and civilisation in China''] {{Webarchive|url=https://web.archive.org/web/20160503082328/https://books.google.com/books?id=BYixSmXUCuMC&pg=PA237 |date=May 3, 2016 }}. Cambridge University Press. {{ISBN|0-521-08571-3}}, pp. 237–250.</ref>
[[File:Nickeline.jpg|thumb|Nickeline/niccolite]]
In medieval Germany, a metallic yellow mineral was found in the Ore 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 to ''[[Unsolved:Devil in Christianity|Old Nick]]''), for besetting the copper. They called this ore {{Lang|de|Kupfernickel}} from German {{Lang|de|Kupfer}} 'copper'.<ref>''Chambers Twentieth Century Dictionary'', p888, W&R Chambers Ltd., 1977.</ref><ref name="JEC-I">{{cite journal|title = The story of Nickel. I. How "Old Nick's" gnomes were outwitted|last = Baldwin|first = W. H.| journal=Journal of Chemical Education|date = 1931|volume = 8|page = 1749|doi = 10.1021/ed008p1749|bibcode = 1931JChEd...8.1749B|issue = 9 }}</ref><ref name="JEC-II">{{cite journal|title = The story of Nickel. II. Nickel comes of age|last = Baldwin|first = W. H.| journal=Journal of Chemical Education|date = 1931|volume = 8|page = 1954|doi = 10.1021/ed008p1954|bibcode = 1931JChEd...8.1954B|issue = 10 }}</ref><ref name="JEC-III">{{cite journal|title = The story of Nickel. III. Ore, matte, and metal|last = Baldwin|first = W. H.| journal=Journal of Chemical Education|date = 1931|volume = 8|page = 2325|doi = 10.1021/ed008p2325|bibcode = 1931JChEd...8.2325B|issue = 12 }}</ref> This ore is now known as the mineral [[Chemistry:Nickeline|nickeline]] (formerly ''niccolite''<ref>Fleisher, Michael and Mandarino, Joel. ''Glossary of Mineral Species''. Tucson, Arizona: Mineralogical Record, 7th ed. 1995.</ref>), a nickel [[Chemistry:Arsenide|arsenide]]. In 1751, Baron [[Biography:Axel Fredrik Cronstedt|Axel Fredrik Cronstedt]] tried to extract copper from kupfernickel at a [[Chemistry:Cobalt|cobalt]] mine in the village of Los, Sweden, and instead produced a white metal that he named ''nickel'' after the spirit that had given its name to the mineral.<ref>{{cite journal|title = The discovery of the elements: III. Some eighteenth-century metals|last = Weeks|first = Mary Elvira|journal=Journal of Chemical Education|date = 1932|volume = 9|issue = 1|page = 22|doi = 10.1021/ed009p22|bibcode = 1932JChEd...9...22W }}</ref> In modern German, Kupfernickel or Kupfer-Nickel designates the alloy [[Chemistry:Cupronickel|cupronickel]].<ref name="crc">{{cite book |author=Hammond, C.R. |author2=Lide, C. R. |chapter=The elements|page=4.22| editor-last = Rumble | editor-first = John R. | date = 2018 | title = CRC Handbook of Chemistry and Physics| edition = 99th | publisher = CRC Press | location = Boca Raton, FL | isbn = 9781138561632|title-link=CRC Handbook of Chemistry and Physics}}</ref>

Originally, the only source for nickel was the rare Kupfernickel. Beginning in 1824, nickel was obtained as a byproduct of [[Chemistry:Cobalt blue|cobalt blue]] production. The first large-scale smelting of nickel began in Norway in 1848 from nickel-rich [[Chemistry:Pyrrhotite|pyrrhotite]]. The introduction of nickel in steel production in 1889 increased the demand for nickel; the nickel deposits of [[Earth:New Caledonia|New Caledonia]], discovered in 1865, provided most of the world's supply between 1875 and 1915. The discovery of the large deposits in the [[Earth:Sudbury Basin|Sudbury Basin]] in Canada in 1883, in Norilsk-Talnakh in Russia in 1920, and in the [[Earth:Merensky Reef|Merensky Reef]] in South Africa in 1924 made large-scale nickel production possible.<ref name="McNeil" />

==Coinage==
[[File:Nickel2.jpg|thumb|right|Dutch coins made of pure nickel]]
Aside from the aforementioned Bactrian coins, nickel was not a component of coins until the mid-19th century.<ref name="toxmetal">{{Cite web |title=The Facts on Nickel |url=https://sites.dartmouth.edu/toxmetal/more-metals/nickel-hidden-in-plain-sight/the-facts-on-nickel/ |access-date=2023-02-19 |website=Dartmouth Toxic Metals}}</ref>

===Canada===
[[Chemistry:Nickel (Canadian coin)|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.<ref>{{cite web|url = http://www.mint.ca/store/mint/learn/circulation-currency-1100028|title = Industrious, enduring–the 5-cent coin|date = 2008|access-date = January 10, 2009|publisher = Royal Canadian Mint|archive-url = https://web.archive.org/web/20090126020102/http://www.mint.ca/store/mint/learn/circulation-currency-1100028|archive-date = January 26, 2009|url-status = live}}</ref> During the war years 1942–1945, most or all nickel was removed from Canadian and US coins to save it for making armor.<ref name="JEC-I" /> Canada used 99.9% nickel from 1968 in its higher-value coins until 2000.<ref>{{cite journal |last1=McLean |first1=Lianne |last2=Yewchuk |first2=Lila |last3=Israel |first3=David M. |last4=Prendiville |first4=Julie S. |title=Acute Onset of Generalized Pruritic Rash in a Toddler |journal=Pediatric Dermatology |date=January 2011 |volume=28 |issue=1 |pages=53–54 |doi=10.1111/j.1525-1470.2010.01367.x |pmid=21276052 |s2cid=207688 |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1525-1470.2010.01367.x |access-date=13 March 2023|url-access=subscription |quote="From 1968 to 1999, Canadian quarters and dimes were minted from 99.9% nickel and nickels from 25 to 99.9% nickel"}}</ref>

===Switzerland===
Coins of nearly pure nickel were first used in 1881 in Switzerland.<ref name="anna" />

===United Kingdom===
Birmingham forged nickel coins in {{Circa|1833}} for trading in Malaysia.<ref>{{cite web|url=http://www.nederlandsemunten.nl/Virtuele_munten_verzameling/Provinciaal/Provincie_Utrecht_1581-1795/Verzameling_nikkelen_dubbele_wapenstuiver_Utrecht-Birmingham_1786.htm|title=nikkelen dubbele wapenstuiver Utrecht|website=nederlandsemunten.nl|access-date=January 7, 2015|archive-url=https://web.archive.org/web/20150107212633/http://www.nederlandsemunten.nl/Virtuele_munten_verzameling/Provinciaal/Provincie_Utrecht_1581-1795/Verzameling_nikkelen_dubbele_wapenstuiver_Utrecht-Birmingham_1786.htm|archive-date=January 7, 2015|url-status=live}}</ref>

===United States===
[[File:Nickel Prices.webp|thumb|300px|Nickel Prices 2018–2022 <br> {{see also|2020s commodities boom}}]]
In the United States, the term "nickel" or "nick" originally applied to the copper-nickel Flying Eagle cent, which replaced copper with 12% nickel 1857–58, then the Indian Head cent of the same alloy from 1859 to 1864. Still later, in 1865, the term designated the three-cent nickel, with nickel increased to 25%. In 1866, the five-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 not [[Physics:Ferromagnetic|ferromagnetic]].

The US nickel coin contains {{convert|0.04|oz|g}} of nickel, which at the April 2007 price was worth 6.5 cents, along with 3.75&nbsp;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. The United 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.<ref>[http://www.usmint.gov/pressroom/index.cfm?action=press_release&ID=724 United States Mint Moves to Limit Exportation & Melting of Coins] {{Webarchive|url=https://web.archive.org/web/20160527072103/http://www.usmint.gov/pressroom//index.cfm?action=press_release&ID=724 |date=May 27, 2016 }}, The United States Mint, press release, December 14, 2006</ref> Violators can be punished with a fine of up to $10,000 and/or a maximum of five years in prison.<ref>{{Cite web|date=2007-04-16|title=Prohibition on the Exportation, Melting, or Treatment of 5-Cent and One-Cent Coins|url=https://www.federalregister.gov/documents/2007/04/16/E7-7088/prohibition-on-the-exportation-melting-or-treatment-of-5-cent-and-one-cent-coins|access-date=2021-08-28|website=Federal Register}}</ref> As of September 19, 2013, the melt value of a US nickel (copper and nickel included) is $0.045 (90% of the face value).<ref>{{cite web| url = http://www.coinflation.com/| title = United States Circulating Coinage Intrinsic Value Table| access-date = September 13, 2013| publisher = Coininflation.com| archive-url = https://web.archive.org/web/20160617065505/http://www.coinflation.com/| archive-date = June 17, 2016| url-status = live}}</ref>

===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 $1 U.S. coins,<ref>{{cite web|url=https://www.usmint.gov/learn/coin-and-medal-programs/coin-specifications|title=Coin Specifications|website=usmint.gov|date=September 20, 2016 |access-date=October 13, 2021}}</ref> and 20p, 50p, £1, and £2 UK 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 with [[Medicine:Nickel allergy|nickel allergy]].<ref name="anna">{{cite news|url=https://www.bbc.co.uk/news/health-22956874|title=A bad penny? New coins and nickel allergy|author=Lacey, Anna|work=BBC Health Check|date=June 22, 2013|access-date=July 25, 2013|archive-url=https://web.archive.org/web/20130807015003/http://www.bbc.co.uk/news/health-22956874|archive-date=August 7, 2013|url-status=live}}</ref>

==World production==
[[File:Nickel world production.svg|thumb|upright=1.4|Time trend of nickel production<ref>{{cite web | url = http://minerals.usgs.gov/minerals/pubs/historical-statistics/ds140-nicke.pdf | last1 = Kelly | first1 = T. D. | last2 = Matos | first2 = G. R. | title = Nickel Statistics | publisher = U.S. Geological Survey | access-date = 2014-08-11 | archive-url = https://web.archive.org/web/20140812212741/http://minerals.usgs.gov/minerals/pubs/historical-statistics/ds140-nicke.pdf | archive-date = August 12, 2014 | url-status = live }}</ref>]]
[[File:Evolution minerai nickel.svg|thumb|upright=1.4|Nickel ores grade evolution in some leading nickel producing countries or regions]]

An estimated 3.3&nbsp;million tonnes (t) of nickel per year are mined worldwide; Indonesia (1,600,000&nbsp;t), the {{wipe|Philippines}} (330,000&nbsp;t), {{wipe|Russia}} (220,000&nbsp;t), [[Earth:New Caledonia|New Caledonia]] ({{wipe|France}}) (190,000&nbsp;t), {{wipe|Australia}} (160,000&nbsp;t) and {{wipe|Canada}} (130,000&nbsp;t) are the largest producers as of 2022.<ref>{{Cite web |title=Mineral Commodity Summaries 2023 - Nickel |url=https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-nickel.pdf |access-date=2 March 2023 |website=US Geological Survey}}</ref> The largest nickel deposits in non-Russian Europe are in {{wipe|Finland}} and Greece. Identified land-based sources averaging at least 1% nickel contain at least 130&nbsp;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 the [[Earth:Pacific Ocean|Pacific Ocean]], especially in an area called the Clarion Clipperton Zone in the form of polymetallic nodules peppering the seafloor at 3.5–6&nbsp;km below [[Sea level|sea level]].<ref name="usgs1">{{cite web|url=http://minerals.usgs.gov/minerals/pubs/commodity/nickel/mcs-2013-nicke.pdf|website=U.S. Geological Survey, Mineral Commodity Summaries|title=Nickel|date=January 2013|access-date=September 20, 2013|archive-url=https://web.archive.org/web/20130509061155/http://minerals.usgs.gov/minerals/pubs/commodity/nickel/mcs-2013-nicke.pdf|archive-date=May 9, 2013|url-status=live}}</ref><ref>{{cite web |last1=Gazley |first1=Michael F. |last2=Tay |first2=Stephie |last3=Aldrich |first3=Sean |title=Polymetallic Nodules |url=https://www.researchgate.net/publication/345988809 |website=Research Gate |publisher=New Zealand Minerals Forum |access-date=27 January 2021}}</ref> These nodules are composed of numerous rare-earth metals and are estimated to be 1.7% nickel.<ref>{{cite book |last1=Mero |first1=J. L. |title=Marine Manganese Deposits |chapter=Chapter 11 Economic Aspects of Nodule Mining |series=Elsevier Oceanography Series |date=1 January 1977 |volume=15 |pages=327–355 |doi=10.1016/S0422-9894(08)71025-0 |isbn=9780444415240 }}</ref> With advances in science and [[Engineering:Engineering|engineering]], regulation is currently being set in place by the International Seabed Authority to ensure that these nodules are collected in an environmentally conscientious manner while adhering to the {{wipe|United Nations}} Sustainable Development Goals.<ref>{{cite web |last1=International Seabed Authority |title=Strategic Plan 2019-2023 |url=https://www.isa.org.jm/files/files/documents/Strategic_Plan_Booklet.pdf |website=isa.org |publisher=International Seabed Authority |access-date=27 January 2021 |archive-date=April 12, 2022 |archive-url=https://web.archive.org/web/20220412025444/https://www.isa.org.jm/files/files/documents/Strategic_Plan_Booklet.pdf |url-status=dead }}</ref>

The one place in the United States where nickel has been profitably mined is Riddle, Oregon, with several square miles of nickel-bearing [[Chemistry:Garnierite|garnierite]] surface deposits. The mine closed in 1987.<ref>{{cite journal|url = http://www.oregongeology.com/sub/publications/OG/OBv15n10.pdf|title = The Nickel Mountain Project|journal = Ore Bin|volume = 15|issue = 10|date = 1953|pages = 59–66|access-date = May 7, 2015|archive-url = https://web.archive.org/web/20120212005749/http://www.oregongeology.com/sub/publications/OG/OBv15n10.pdf|archive-date = February 12, 2012|url-status = dead|df = mdy-all}}</ref><ref>{{cite web|title=Environment Writer: Nickel |publisher=National Safety Council |url=http://www.environmentwriter.org/resources/backissues/chemicals/nickel.htm |archive-url=https://web.archive.org/web/20060828211637/http://www.environmentwriter.org/resources/backissues/chemicals/nickel.htm |url-status=dead |archive-date=2006-08-28 |date=2006 |access-date=January 10, 2009 }}</ref> The Eagle mine project is a new nickel mine in Michigan's Upper Peninsula. Construction was completed in 2013, and operations began in the third quarter of 2014.<ref name="eagle">{{cite web |url=http://www.lundinmining.com/s/QOU.asp?ReportID=718088 |title=Operations & Development |publisher=Lundin Mining Corporation |access-date=2014-08-10 |archive-url=https://web.archive.org/web/20151118181320/http://www.lundinmining.com/s/QOU.asp?ReportID=718088 |archive-date=November 18, 2015 |url-status=dead |df=mdy-all }}</ref> In the first full year of operation, the Eagle Mine produced 18,000 t.<ref name="eagle" />

{{Anchor|Extraction and purification}}

==Production==
[[File:Nickel extraction.svg|thumb|left|Evolution of the annual nickel extraction, according to ores]]

Nickel is obtained through [[Engineering:Extractive metallurgy|extractive metallurgy]]: it is extracted from ore by conventional roasting and reduction processes that yield metal of greater than 75% purity. In many [[Chemistry:Stainless steel|stainless steel]] applications, 75% pure nickel can be used without further purification, depending on impurities.<ref name=NiCmpds/>

Traditionally, most sulfide ores are processed using pyrometallurgical techniques to produce a [[Engineering:Matte (metallurgy)|matte]] for further refining. Recent advances in [[Chemistry:Hydrometallurgy|hydrometallurgical techniques]] result in significantly purer metallic nickel product. Most sulfide deposits have traditionally been processed by concentration through a [[Chemistry:Froth flotation|froth flotation]] process followed by pyrometallurgical extraction. In hydrometallurgical processes, nickel sulfide ores are concentrated with [[Chemistry:Froth flotation|flotation]] (differential flotation if Ni/Fe ratio is too low) and then smelted. The nickel matte is further processed with the Sherritt-Gordon process. First, copper is removed by adding [[Chemistry:Hydrogen sulfide|hydrogen 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%.<ref>{{Cite journal |last1=Ichlas |first1=Zela Tanlega |last2=Purwadaria |first2=Sunara |title=Solvent extraction separation of nickel and cobalt from a sulfate solution containing iron(II) and magnesium using versatic 10 |journal=1st International Process Metallurgy Conference |series=AIP Conference Proceedings |date=2017 |volume=1805 |issue=1 |pages=030003 |doi=10.1063/1.4974414|bibcode=2017AIPC.1805c0003I |doi-access=free }}</ref>
[[File:Nickel electrolytic and 1cm3 cube.jpg|thumb|[[Chemistry:Electrolysis|Electrolytically refined]] nickel nodule, with green, crystallized nickel-electrolyte salts visible in the pores]]

===Electrorefining===
A second common refining process is leaching the metal matte into a nickel salt solution, followed by [[Physics:Electrowinning|electrowinning]] the nickel from solution by plating it onto a cathode as electrolytic nickel.<ref name="ASM" />

===Mond process===
[[File:Nickel kugeln.jpg|thumb|left|Highly purified nickel spheres made by the Mond process]]
{{Main|Chemistry:Mond process}}
The purest metal is obtained from nickel oxide by the [[Chemistry:Mond process|Mond process]], which gives a purity of over 99.99%.<ref>{{cite journal|last1= Mond |first1=L. |last2=Langer |first2=K. |last3=Quincke |first3=F.| title= Action of carbon monoxide on nickel| journal=Journal of the Chemical Society|date=1890| pages=749–753|doi = 10.1039/CT8905700749|volume= 57|url=https://zenodo.org/record/2160347 }}</ref> The process was patented by Ludwig Mond and has been in industrial use since before the beginning of the 20th century. In this process, nickel is reacted with [[Chemistry:Carbon monoxide|carbon monoxide]] in the presence of a sulfur catalyst at around 40–80&nbsp;°C to form nickel carbonyl. In a similar reaction with iron, [[Chemistry:Iron pentacarbonyl|iron pentacarbonyl]] can form, though this reaction is slow. If necessary, the nickel may be separated by distillation. [[Chemistry:Dicobalt octacarbonyl|Dicobalt octacarbonyl]] is also formed in nickel distillation as a by-product, but it decomposes to [[Chemistry:Tetracobalt dodecacarbonyl|tetracobalt dodecacarbonyl]] at the reaction temperature to give a non-volatile solid.<ref name="ullmann-1">{{Ullmann|author=Kerfoot, Derek G. E. |title=Nickel|doi=10.1002/14356007.a17_157|year=2005}}</ref>

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&nbsp;°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".<ref>{{cite book|author=Neikov, Oleg D.|author2=Naboychenko, Stanislav|author3=Gopienko, Victor G|author4=Frishberg, Irina V|name-list-style=amp|title=Handbook of Non-Ferrous Metal Powders: Technologies and Applications|url=https://books.google.com/books?id=6aP3te2hGuQC&pg=PA371|access-date=January 9, 2012|date=January 15, 2009|publisher=Elsevier|isbn=978-1-85617-422-0|pages=371–|archive-url=https://web.archive.org/web/20130529010927/http://books.google.com/books?id=6aP3te2hGuQC&pg=PA371|archive-date=May 29, 2013|url-status=live}}</ref>

===Market value===
The market price of nickel surged throughout 2006 and the early months of 2007; {{as of|lc=y|2007|4|5|df=US}}, the metal was trading at {{wipe|United States dollar}}$52,300/[[Tonne|tonne]] or $1.47/oz.<ref name="LME">{{cite web| url = http://www.lme.com/nickel_graphs.asp| title = LME nickel price graphs| publisher = London Metal Exchange| access-date = June 6, 2009| url-status = dead| archive-url = https://web.archive.org/web/20090228180212/http://www.lme.com/nickel_graphs.asp| archive-date = February 28, 2009| df = mdy-all}}</ref> The price later fell dramatically; {{as of|lc=y|September 2017}}, the metal was trading at $11,000/tonne, or $0.31/oz.<ref>{{cite web|url=https://www.lme.com/metals/non-ferrous/nickel#tabIndex=0|title=London Metal Exchange|publisher=LME.com|archive-url=https://web.archive.org/web/20170920092525/https://www.lme.com/metals/non-ferrous/nickel#tabIndex=0|archive-date=September 20, 2017|url-status=live}}</ref> During the 2022 Russian invasion of Ukraine, worries about sanctions on Russian nickel exports triggered a short squeeze, causing the price of nickel to quadruple in just two days, reaching US$100,000 per tonne.<ref>{{cite news |last1=Hume |first1=Neil |last2=Lockett |first2=Hudson |title=LME introduces emergency measures as nickel hits $100,000 a tonne |url=https://www.ft.com/content/0269cdda-ef67-43c8-b820-a919c919b5fa |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/0269cdda-ef67-43c8-b820-a919c919b5fa |archive-date=December 10, 2022 |url-access=subscription |url-status=live |access-date=8 March 2022 |work=[[Social:Financial Times|Financial Times]] |date=8 March 2022}}</ref><ref>{{cite news |last1=Burton |first1=Mark |last2=Farchy |first2=Jack |last3=Cang |first3=Alfred |title=LME Halts Nickel Trading After Unprecedented 250% Spike |url=https://www.bloomberg.com/news/articles/2022-03-08/lme-suspends-nickel-trading-after-unprecedented-price-spike |access-date=8 March 2022 |work={{wipe|Bloomberg News}}}}</ref> The [[Organization:London Metal Exchange|London Metal Exchange]] cancelled contracts worth $3.9&nbsp;billion and suspended nickel trading for over a week.<ref>{{cite news |last1=Farchy |first1=Jack |last2=Cang |first2=Alfred |last3=Burton |first3=Mark |title=The 18 Minutes of Trading Chaos That Broke the Nickel Market |url=https://www.bloomberg.com/news/articles/2022-03-14/inside-nickel-s-short-squeeze-how-price-surges-halted-lme-trading |work={{wipe|Bloomberg News}} |date=14 March 2022}}</ref> 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 a [[Finance:Commodity|commodity]] on the exchanges, but most of the world's supply is either in ferro-nickel alloys or lower-grade purities.<ref>{{Cite news |last=Home |first=Andy |date=2022-03-10 |title=Column: Nickel, the devil's metal with a history of bad behaviour|work=Reuters |url=https://www.reuters.com/markets/commodities/nickel-devils-metal-with-history-bad-behaviour-2022-03-10/ |access-date=2022-03-10}}</ref>

==Applications==
[[File:Ni foam.jpg|thumb|Nickel foam (top) and its internal structure (bottom)]]
Global use of nickel is currently 68% in stainless steel, 10% in nonferrous [[Chemistry:Alloy|alloy]]s, 9% [[Engineering:Electroplating|electroplating]], 7% alloy steel, 3% foundries, and 4% other (including batteries).<ref name="Nickel Use In Society" />

Nickel is used in many recognizable industrial and consumer products, including [[Chemistry:Stainless steel|stainless steel]], [[Physics:Alnico|alnico]] magnets, coinage, [[Engineering:Rechargeable battery|rechargeable batteries]] (e.g. [[Chemistry:Nickel–iron battery|nickel–iron]]), electric guitar strings, microphone capsules, plating on plumbing fixtures,<ref>{{Cite book|url=https://archive.org/details/americanplumbing00newyrich|title=American Plumbing Practice: From the Engineering Record (Prior to 1887 the Sanitary Engineer.) A Selected Reprint of Articles Describing Notable Plumbing Installations in the United States, and Questions and Answers on Problems Arising in Plumbing and House Draining. With Five Hundred and Thirty-six Illustrations|date=1896|publisher=Engineering record|page=[https://archive.org/details/americanplumbing00newyrich/page/119 119]|access-date=May 28, 2016}}</ref> and special alloys such as [[Physics:Permalloy|permalloy]], [[Chemistry:Elinvar|elinvar]], and [[Chemistry:Invar|invar]]. 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 ([[Chemistry:Inconel|Inconel]], [[Chemistry:Incoloy|Incoloy]], [[Chemistry:Monel|Monel]], [[Chemistry:Nimonic|Nimonic]]).<ref name="ASM">{{cite book|chapter-url = https://books.google.com/books?id=IePhmnbmRWkC|title = ASM Specialty Handbook: Nickel, Cobalt, and Their Alloys|first = Joseph R.|last = Davis|publisher=ASM International|date = 2000|isbn = 978-0-87170-685-0|pages = 7–13|chapter = Uses of Nickel}}</ref>

[[File:MagnetEZ.jpg|thumb|left|A "horseshoe magnet" made of alnico nickel alloy]]

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.<ref name="toxmetal"/>

Nickel is an excellent alloying agent for certain precious metals and is used in the [[Metallurgical assay|fire assay]] as a collector of [[Earth:Platinum group|platinum 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 (mainly [[Chemistry:Platinum|platinum]] and [[Chemistry:Palladium|palladium]]); examples are Norilsk, Russia and the Sudbury Basin, Canada.<ref>{{Cite web |title=Platinum-Group Element - an overview  |url=https://www.sciencedirect.com/topics/materials-science/platinum-group-element |access-date=2022-10-18 |website=ScienceDirect Topics |url-status=live |archive-url=https://web.archive.org/web/20221018160358/https://www.sciencedirect.com/topics/materials-science/platinum-group-element |archive-date=2022-10-18 }}</ref>

[[Chemistry:Metal foam|Nickel foam]] or nickel mesh is used in [[Physics:Gas diffusion electrode|gas diffusion electrode]]s for alkaline fuel cells.<ref>{{cite book|author=Kharton, Vladislav V.|title=Solid State Electrochemistry II: Electrodes, Interfaces and Ceramic Membranes|url=https://books.google.com/books?id=5n5Fwf5D2EMC&pg=PT166|date=2011|publisher=Wiley-VCH|isbn=978-3-527-32638-9|pages=166–|access-date=June 27, 2015|archive-url=https://web.archive.org/web/20150910120540/https://books.google.com/books?id=5n5Fwf5D2EMC&pg=PT166|archive-date=September 10, 2015|url-status=live}}</ref><ref>{{cite web|title = A New Cathode Design for Alkaline Fuel Cells (AFCs)|author=Bidault, F.|author2=Brett, D. J. L.|author3=Middleton, P. H.|author4=Brandon, N. P.|url = http://perso.ensem.inpl-nancy.fr/Olivier.Lottin/FDFC08/Bidault.pdf|archive-url = https://web.archive.org/web/20110720233739/http://perso.ensem.inpl-nancy.fr/Olivier.Lottin/FDFC08/Bidault.pdf|archive-date = 2011-07-20|publisher=Imperial College London}}</ref>

Nickel and its alloys are often used as catalysts for [[Chemistry:Hydrogenation|hydrogenation]] reactions. [[Chemistry:Raney nickel|Raney nickel]], a finely divided nickel-aluminium alloy, is one common form, though related catalysts are also used, including Raney-type catalysts.<ref>{{cite journal |last1=Tucker |first1=S. Horwood |title=Catalytic hydrogenation using Raney nickel |journal=Journal of Chemical Education |date=September 1950 |volume=27 |issue=9 |page=489 |doi=10.1021/ed027p489 |bibcode=1950JChEd..27..489T |url=https://pubs.acs.org/doi/10.1021/ed027p489 |access-date=21 April 2023}}</ref>
	
Nickel is naturally magnetostrictive: in the presence of a [[Physics:Magnetic field|magnetic field]], the material undergoes a small change in length.<ref>[https://web.archive.org/web/20130905155229/http://aml.seas.ucla.edu/research/areas/magnetostrictive/overview.htm Magnetostrictive Materials Overview]. [[Organization:University of California, Los Angeles|University of California, Los Angeles]].</ref><ref>{{cite book |publisher=Umi Dissertation Publishing| title = High Frequency High Amplitude Magnetic Field Driving System for Magnetostrictive Actuators | first1 =Raghavendra | last1 = Angara | page = 5| isbn = 9781109187533 | date = 2009 }}</ref> The [[Physics:Magnetostriction|magnetostriction]] of nickel is on the order of 50&nbsp;ppm and is negative, indicating that it contracts.<ref>{{Cite journal |last1=Sofronie |first1=Mihaela |last2=Tolea |first2=Mugurel |last3=Popescu |first3=Bogdan |last4=Enculescu |first4=Monica |last5=Tolea |first5=Felicia |date=2021-09-07 |title=Magnetic and Magnetostrictive Properties of Ni50Mn20Ga27Cu3 Rapidly Quenched Ribbons |journal=Materials |volume=14 |issue=18 |pages=5126 |doi=10.3390/ma14185126 |issn=1996-1944 |pmc=8471753 |pmid=34576350|bibcode=2021Mate...14.5126S |doi-access=free }}</ref>

Nickel is used as a binder in the cemented [[Chemistry:Tungsten carbide|tungsten 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.<ref>{{cite journal|journal=Soviet Powder Metallurgy and Metal Ceramics| title = Structure and properties of tungsten carbide hard alloys with an alloyed nickel binder| doi = 10.1007/BF00796252|date = 1992|last1 = Cheburaeva|first1 = R. F.|last2 = Chaporova|first2 = I. N.|last3 = Krasina|first3 = T. I.|volume = 31|pages = 423–425|issue=5| s2cid = 135714029}}</ref>

{{chem|63|Ni}}, with a [[Physics:Half-life|half-life]] of 100.1 years, is useful in [[Physics:Krytron|krytron]] devices as a [[Physics:Beta particle|beta particle]] (high-speed [[Physics:Electron|electron]]) emitter to make [[Physics:Ionization|ionization]] by the keep-alive electrode more reliable.<ref>{{cite web|title=Krytron Pulse Power Switching Tubes|url=http://www.siliconinvestigations.com/KRYT/Krytron.HTM|archive-url=https://web.archive.org/web/20110716071203/http://www.siliconinvestigations.com/KRYT/Krytron.HTM|url-status=dead|archive-date=2011-07-16|publisher=Silicon Investigations|date=2011 }}</ref> It is being investigated as a power source for [[Physics:Betavoltaic device|betavoltaic batteries]].<ref>{{cite journal | display-authors=1 | first1=Y. R. | last1=Uhm | first2=B. G. | last2=Choi | first3=J. B. | last3=Kim | first4=D.-H. | last4=Jeong | first5=K. J. | last5=Son | title=Study of a Betavoltaic Battery Using Electroplated Nickel-63 on Nickel Foil as a Power Source | journal=Nuclear Engineering and Technology | volume=48 | issue=3 | pages=773–777 | date=June 2016 | doi=10.1016/j.net.2016.01.010 | doi-access=free }}</ref><ref>{{cite journal | title=High power density nuclear battery prototype based on diamond Schottky diodes | first1=V. S. | last1=Bormashov | first2=S. Yu. | last2=Troschiev | first3=S. A. | last3=Tarelkin | first4=A. P. | last4=Volkov | first5=D. V. | last5=Teteruk | first6=A. V. | last6=Golovanov | first7=M. S. | last7=Kuznetsov | first8=N. V. | last8=Kornilov | first9=S. A. | last9=Terentiev | first10=V. D. | last10=Blank | display-authors=1 | journal=Diamond and Related Materials | volume=84 | date=April 2018 | pages=41–47 | doi=10.1016/j.diamond.2018.03.006 | bibcode=2018DRM....84...41B | doi-access=free }}</ref>

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.<ref name="Nickel Use In Society" />

[[Chemistry:Raney nickel|Raney nickel]] is widely used for [[Chemistry:Hydrogenation|hydrogenation]] of [[Chemistry:Saturated and unsaturated compounds|unsaturated]] oils to make margarine, and substandard margarine and leftover oil may contain nickel as a contaminant. Forte et al. found that type 2 diabetic patients have 0.89&nbsp;ng/mL of Ni in the blood relative to 0.77&nbsp;ng/mL in control subjects.<ref>{{Cite journal|title=Metals in the pathogenesis of type 2 diabetes|first1=Abdul Rehman|last1=Khan|first2=Fazli Rabbi|last2=Awan|date=January 8, 2014|journal=Journal of Diabetes and Metabolic Disorders|volume=13|issue = 1|pages=16|doi=10.1186/2251-6581-13-16|pmid=24401367|pmc=3916582 |doi-access=free }}</ref>

[[Physics:Nickel titanium|Nickel titanium]] is an alloy of roughly equal atomic percentages of its constituent metals which exhibits two closely related and unique properties: the shape memory effect and superelasticity.

== Biological role ==
It was not recognized until the 1970s, but nickel is known to play an important role in the biology of some plants, [[Biology:Bacteria|bacteria]], [[Biology:Archaea|archaea]], and [[Biology:Fungi|fungi]].<ref name="Sigel">{{cite book|title=Nickel and Its Surprising Impact in Nature|editor=Astrid Sigel|editor2=Helmut Sigel|editor3=Roland K. O. Sigel |publisher=Wiley |date=2008 |series=Metal Ions in Life Sciences|volume=2 |isbn=978-0-470-01671-8 }}</ref><ref name="Sydor">{{cite book|last1=Sydor|first1=Andrew|last2=Zamble|first2=Deborah|title=Metallomics and the Cell |chapter=Nickel Metallomics: General Themes Guiding Nickel Homeostasis |series=Metal Ions in Life Sciences |editor1-last=Banci|editor1-first=Lucia|date=2013|volume=12|publisher=Springer|location=Dordrecht|isbn=978-94-007-5561-1|pages=375–416|doi=10.1007/978-94-007-5561-1_11|pmid=23595678}}</ref><ref>{{cite book|author1=Zamble, Deborah |author2=Rowińska-Żyrek, Magdalena |author3=Kozlowski, Henryk |title=The Biological Chemistry of Nickel|url=https://books.google.com/books?id=LQifDgAAQBAJ|date=2017|publisher=Royal Society of Chemistry|isbn=978-1-78262-498-1}}</ref> Nickel enzymes such as [[Biology:Urease|urease]] are considered virulence factors in some organisms.<ref>{{Cite journal|last1=Covacci|first1=Antonello|last2=Telford|first2=John L.|last3=Giudice|first3=Giuseppe Del|last4=Parsonnet|first4=Julie|author4-link=Julie Parsonnet|last5=Rappuoli|first5=Rino|date=1999-05-21|title=''Helicobacter pylori'' Virulence and Genetic Geography|journal=Science|volume=284|issue=5418|pages=1328–1333|doi=10.1126/science.284.5418.1328|pmid=10334982|bibcode=1999Sci...284.1328C|s2cid=10376008}}</ref><ref>{{Cite journal|last1=Cox|first1=Gary M.|last2=Mukherjee|first2=Jean|last3=Cole|first3=Garry T.|last4=Casadevall|first4=Arturo|last5=Perfect|first5=John R.|date=2000-02-01|title=Urease as a Virulence Factor in Experimental Cryptococcosis|journal=Infection and Immunity|volume=68|issue=2|pages=443–448|doi=10.1128/IAI.68.2.443-448.2000|pmid=10639402|pmc=97161}}</ref> Urease catalyzes hydrolysis of [[Chemistry:Urea|urea]] to form [[Chemistry:Ammonia|ammonia]] and [[Chemistry:Carbamate|carbamate]].<ref name="Sydor" /><ref name="Sigel" /> [[Biology:NiFe hydrogenase|NiFe hydrogenase]]s can catalyze oxidation of {{chem2|[[Chemistry:Hydrogen|H]]2}} to form protons and electrons; and also the reverse reaction, the reduction of protons to form hydrogen gas.<ref name="Sydor" /><ref name="Sigel" /> A nickel-tetrapyrrole coenzyme, [[Chemistry:Cofactor F430|cofactor F430]], is present in methyl [[Chemistry:Coenzyme M|coenzyme M]] reductase, which can catalyze the formation of methane, or the reverse reaction, in [[Biology:Methanogen|methanogen]]ic [[Biology:Archaea|archaea]] (in +1 oxidation state).<ref>
{{cite book
|first1=Ragdale
|last1= Stephen W.
|chapter= 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
|editor=Peter M.H. Kroneck
|editor2=Martha E. Sosa Torres
|title=The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment
|series=Metal Ions in Life Sciences
|volume=14
|date=2014
|publisher=Springer
|pages=125–145
|doi=10.1007/978-94-017-9269-1_6
|pmid= 25416393
|isbn= 978-94-017-9268-4
}}
</ref> One of the carbon monoxide dehydrogenase enzymes consists of an [[Chemistry:Iron|Fe]]-Ni-[[Chemistry:Sulfur|S]] cluster.<ref>
{{cite book |first2=Stephen W.|last2= Ragsdale|first1=Vincent C.-C.|last1= Wang|first3=Fraser A.|last3= Armstrong|chapter= Investigations of the Efficient Electrocatalytic Interconversions of Carbon Dioxide and Carbon Monoxide by Nickel-Containing Carbon Monoxide Dehydrogenases|editor=Peter M.H. Kroneck|editor2=Martha E. Sosa Torres|title=The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment|series=Metal Ions in Life Sciences|volume=14|date=2014|publisher=Springer|pages= 71–97|doi=10.1007/978-94-017-9269-1_4|pmid= 25416391|pmc= 4261625|isbn= 978-94-017-9268-4}}</ref> Other nickel-bearing enzymes include a rare bacterial class of [[Biology:Superoxide dismutase|superoxide dismutase]]<ref>{{cite journal|last = Szilagyi| first = R. K.|display-authors=4|author2=Bryngelson, P. A. |author3=Maroney, M. J. |author4=Hedman, B. |author5=Hodgson, K. O. |author6= Solomon, E. I. |title = S K-Edge X-ray Absorption Spectroscopic Investigation of the Ni-Containing Superoxide Dismutase Active Site: New Structural Insight into the Mechanism|journal=Journal of the American Chemical Society|date = 2004|volume = 126|issue = 10|pages = 3018–3019|doi = 10.1021/ja039106v|pmid = 15012109}}</ref> and glyoxalase I enzymes in bacteria and several eukaryotic trypanosomal parasites<ref>{{cite journal |author=Greig N |author2=Wyllie S |author3=Vickers TJ|author4=Fairlamb AH |title=Trypanothione-dependent glyoxalase I in Trypanosoma cruzi |journal=Biochemical Journal |volume=400 |issue=2 |pages=217–23 |date=2006 |pmid=16958620 |doi=10.1042/BJ20060882 |pmc=1652828}}</ref> (in other organisms, including yeast and mammals, this enzyme contains divalent {{chem2|[[Chemistry:Zinc|Zn]](2+)}}).<ref name="aronsson_1978">{{cite journal | author = Aronsson A-C | author2 = Marmstål E | author3 = Mannervik B | date = 1978 | title = Glyoxalase I, a zinc metalloenzyme of mammals and yeast | journal = Biochemical and Biophysical Research Communications | volume = 81 | issue = 4 | pages = 1235–1240 | doi = 10.1016/0006-291X(78)91268-8 | pmid = 352355}}</ref><ref name="ridderstroem_1996">{{cite journal | author = Ridderström M | author2 = Mannervik B | date = 1996 | title = Optimized heterologous expression of the human zinc enzyme glyoxalase I | journal = Biochemical Journal | volume = 314 | pages = 463–467 | pmid = 8670058 | pmc = 1217073 | issue = Pt 2 | doi=10.1042/bj3140463}}</ref><ref>{{cite journal | author = Saint-Jean AP | author2 = Phillips KR | author3 = Creighton DJ| author4 = Stone MJ | date = 1998 | title = Active monomeric and dimeric forms of Pseudomonas putida glyoxalase I: evidence for 3D domain swapping | journal = Biochemistry | volume = 37 | pages = 10345–10353 | doi = 10.1021/bi980868q | pmid = 9671502 | issue = 29}}</ref><ref>{{cite journal|last = Thornalley|first = P. J.|title = Glyoxalase I—structure, function and a critical role in the enzymatic defence against glycation|journal=Biochemical Society Transactions|date = 2003|volume = 31|pages = 1343–1348|doi = 10.1042/BST0311343|pmid = 14641060|issue = Pt 6|title-link = glycation}}</ref><ref>{{cite book | author = Vander Jagt DL | date = 1989 | chapter = Unknown chapter title | title = Coenzymes and Cofactors VIII: Glutathione Part A | editor = D Dolphin | editor2 = R Poulson | editor3 = O Avramovic | publisher = John Wiley and Sons | location = New York}}</ref>

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 a [[Biology:Prebiotic (nutrition)|prebiotic]].<ref>{{cite book |first1=Barbara|last1=Zambelli|first2=Stefano|last2=Ciurli|chapter=Nickel and Human Health |editor=Astrid Sigel|editor2=Helmut Sigel|editor3=Roland K. O. Sigel|title=Interrelations between Essential Metal Ions and Human Diseases|series=Metal Ions in Life Sciences|volume=13|date=2013|publisher=Springer|pages=321–357|doi=10.1007/978-94-007-7500-8_10|pmid=24470096|isbn=978-94-007-7499-5}}</ref> The US Institute of Medicine has not confirmed that nickel is an essential nutrient for humans, so neither a Recommended Dietary Allowance (RDA) nor an Adequate Intake have been established. The tolerable upper intake level of dietary nickel is 1&nbsp;mg/day as soluble nickel salts. Estimated dietary intake is 70 to 100&nbsp;µg/day; less than 10% is absorbed. What is absorbed is excreted in urine.<ref>Nickel. IN: [https://www.nap.edu/read/10026/chapter/15 Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Copper] {{Webarchive|url=https://web.archive.org/web/20170922174144/https://www.nap.edu/read/10026/chapter/15 |date=September 22, 2017 }}. National Academy Press. 2001, PP. 521–529.</ref> Relatively large amounts of nickel – comparable to the estimated average ingestion above – [[Engineering:Leaching|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&nbsp;µg.<ref>{{cite journal|author=Kamerud KL|author2=Hobbie KA|author3=Anderson KA|title=Stainless Steel Leaches Nickel and Chromium into Foods During Cooking|journal=Journal of Agricultural and Food Chemistry |date=August 28, 2013|doi=10.1021/jf402400v|pmid=23984718|volume=61|issue=39|pages=9495–501|pmc=4284091}}</ref><ref>{{cite journal|author=Flint GN|author2=Packirisamy S|title=Purity of food cooked in stainless steel utensils|journal=Food Additives & Contaminants |date=1997|volume=14|issue=2|pages=115–26|doi=10.1080/02652039709374506|pmid=9102344}}</ref>

Nickel released from Siberian Traps volcanic eruptions is suspected of helping the growth of ''[[Biology:Methanosarcina|Methanosarcina]]'', a genus of euryarchaeote archaea that produced [[Chemistry:Methane|methane]] in the [[Earth:Permian–Triassic extinction event|Permian–Triassic extinction event]], the biggest known mass extinction.<ref>
{{cite web |url= http://www.space.com/26654-microbe-innovation-started-largest-earth-extinction.html|title= Microbe's Innovation May Have Started Largest Extinction Event on Earth|last= Schirber|first= Michael|date= July 27, 2014|publisher= Astrobiology Magazine|website= Space.com|quote= .... That spike in nickel allowed methanogens to take off.|access-date= July 29, 2014|archive-url= https://web.archive.org/web/20140729090332/http://www.space.com/26654-microbe-innovation-started-largest-earth-extinction.html|archive-date= July 29, 2014|url-status= live}}</ref>

==Toxicity==
{{Further|Medicine:Nickel allergy}}
{{Chembox
| container_only = yes
|Section7={{Chembox Hazards
| ExternalSDS =
| GHSPictograms = {{GHS08}}{{GHS07}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|317|351|372|412}}
| PPhrases = {{P-phrases|201|202|260|264|270|272|273|280|302+352|308+313|333+313|363|405|501}}<ref>{{Cite web | url=https://www.sigmaaldrich.com/catalog/product/aldrich/203904?lang=en&region=US | title=Nickel 203904 | publisher=Sigma Aldrich | access-date=January 26, 2020 | archive-url=https://web.archive.org/web/20200126174018/https://www.sigmaaldrich.com/catalog/product/aldrich/203904%3Flang%3Den%26region%3DUS | archive-date=January 26, 2020 | url-status=bot: unknown }}</ref>
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 0
| NFPA-S = <!--<ref>{{Cite web |url=https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=357553&brand=ALDRICH&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F357553%3Flang%3Den |title=Archived copy |access-date=October 3, 2018 |archive-url=https://web.archive.org/web/20181003104944/https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=357553&brand=ALDRICH&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F357553%3Flang%3Den |archive-date=October 3, 2018 |url-status=live }}</ref>-->
}}
}}
 	
The major source of nickel exposure is oral consumption, as nickel is essential to plants.<ref>{{cite journal |doi=10.1016/j.yrtph.2017.03.011 |pmid=28300623 |title=Derivation of an oral toxicity reference value for nickel |journal=Regulatory Toxicology and Pharmacology |volume=87 |pages=S1–S18 |year=2017 |last1=Haber |first1=Lynne T |last2=Bates |first2=Hudson K |last3=Allen |first3=Bruce C |last4=Vincent |first4=Melissa J |last5=Oller |first5=Adriana R |doi-access=free }}</ref> Typical background concentrations of nickel do not exceed 20&nbsp;ng/m{{sup|3}} in air, 100&nbsp;mg/kg in soil, 10&nbsp;mg/kg in vegetation, 10&nbsp;μg/L in freshwater and 1&nbsp;μg/L in seawater.<ref>{{Cite book|last=Rieuwerts|first=John|url=https://www.worldcat.org/oclc/886492996|title=The Elements of Environmental Pollution|publisher=Earthscan Routledge|year=2015|isbn=978-0-415-85919-6|location=London and New York|pages=255|oclc=886492996}}</ref> Environmental concentrations may be increased by human pollution. For example, nickel-plated faucets may contaminate water and soil; mining and smelting may dump nickel into [[Earth:Wastewater|wastewater]]; nickel–steel [[Chemistry:Alloy|alloy]] cookware and nickel-pigmented dishes may release nickel into food. Air may be polluted by nickel ore refining and fossil fuel combustion. Humans may absorb nickel directly from [[Chemistry:Tobacco smoke|tobacco smoke]] and skin contact with jewelry, [[Medicine:Shampoo|shampoo]]s, detergents, and [[Finance:Coin|coin]]s. A less common form of chronic exposure is through [[Engineering:Hemodialysis|hemodialysis]] as traces of nickel ions may be absorbed into the plasma from the chelating action of [[Biology:Albumin|albumin]].{{Citation needed|date=January 2021}}

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, even [[Biology:Carcinogen|carcinogen]]ic, and constitute an occupational hazard.<ref>{{cite book|last1 = Butticè|first1 = Claudio|editor1-last = Colditz|editor1-first = Graham A.|title = The SAGE Encyclopedia of Cancer and Society|date = 2015|publisher = SAGE Publications, Inc.|location = Thousand Oaks|isbn = 9781483345734|pages = 828–831|edition = Second|chapter = Nickel Compounds}}</ref>

Nickel compounds are classified as human carcinogens<ref name="Nickel and nickel compounds">IARC (2012). [https://monographs.iarc.fr/ENG/Monographs/vol100C/mono100C-10.pdf "Nickel and nickel compounds"] {{Webarchive|url=https://web.archive.org/web/20170920044638/https://monographs.iarc.fr/ENG/Monographs/vol100C/mono100C-10.pdf |date=September 20, 2017 }} in ''IARC Monogr Eval Carcinog Risks Hum''. Volume 100C. pp. 169–218.</ref><ref name="Reg 1272/2008">Regulation (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]. [http://www.eur-lex.europa.eu/legal-content/en/TXT/?uri=CELEX%3A32008R1272 Annex VI] {{Webarchive|url=https://web.archive.org/web/20190314212328/https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008R1272 |date=March 14, 2019 }}. Accessed July 13, 2017.</ref><ref name="GHS">[https://www.unece.org/fileadmin/DAM/trans/danger/publi/ghs/ghs_rev05/English/ST-SG-AC10-30-REv5e.pdf Globally Harmonised System of Classification and Labelling of Chemicals (GHS)] {{Webarchive|url=https://web.archive.org/web/20170829031509/http://www.unece.org/fileadmin/DAM/trans/danger/publi/ghs/ghs_rev05/English/ST-SG-AC10-30-Rev5e.pdf |date=August 29, 2017 }}, 5th ed., United Nations, New York and Geneva, 2013.</ref><ref name="Carcinogens">National Toxicology Program. (2016). [https://ntp.niehs.nih.gov/pubhealth/roc/index-1.html "Report on Carcinogens"] {{Webarchive|url=https://web.archive.org/web/20170920044600/https://ntp.niehs.nih.gov/pubhealth/roc/index-1.html |date=September 20, 2017 }}, 14th ed. Research Triangle Park, NC: U.S. Department of Health and Human Services, Public Health Service.</ref> based on increased respiratory cancer risks observed in epidemiological studies of sulfidic ore refinery workers.<ref name="Nickel Carcinogenesis in Man">{{cite journal|pmid=2185539|jstor=40965957|year=1990|title=Report of the International Committee on Nickel Carcinogenesis in Man|journal=Scandinavian Journal of Work, Environment & Health|volume=16|issue=1 Spec No|pages=1–82|doi=10.5271/sjweh.1813|doi-access=free}}</ref> This is supported by the positive results of the NTP bioassays with Ni sub-sulfide and Ni oxide in rats and mice.<ref name="Studies of Nickel Subsulfide">{{cite journal|pmid=12594522|year=1996|title=NTP Toxicology and Carcinogenesis Studies of Nickel Subsulfide (CAS No. 12035-72-2) in F344 Rats and B6C3F1 Mice (Inhalation Studies)|journal=National Toxicology Program Technical Report Series|volume=453|pages=1–365|author1=National Toxicology Program}}</ref><ref>{{cite journal|pmid=12594524|year=1996|title=NTP Toxicology and Carcinogenesis Studies of Nickel Oxide (CAS No. 1313-99-1) in F344 Rats and B6C3F1 Mice (Inhalation Studies)|journal=National Toxicology Program Technical Report Series|volume=451|pages=1–381|author1=National Toxicology Program}}</ref> 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.<ref>{{cite journal|pmid=22158127|pmc=3243677|year=2011|last1=Cogliano|first1=V. J|title=Preventable exposures associated with human cancers|journal=JNCI Journal of the National Cancer Institute|volume=103|issue=24|pages=1827–39|last2=Baan|first2=R|last3=Straif|first3=K|last4=Grosse|first4=Y|last5=Lauby-Secretan|first5=B|last6=El Ghissassi|first6=F|last7=Bouvard|first7=V|last8=Benbrahim-Tallaa|first8=L|last9=Guha|first9=N|last10=Freeman|first10=C|last11=Galichet|first11=L|last12=Wild|first12=C. P|doi=10.1093/jnci/djr483}}</ref><ref>{{cite journal|pmid=17692353|year=2007|last1=Heim|first1=K. E|title=Oral carcinogenicity study with nickel sulfate hexahydrate in Fischer 344 rats|journal=Toxicology and Applied Pharmacology|volume=224|issue=2|pages=126–37|last2=Bates|first2=H. K|last3=Rush|first3=R. E|last4=Oller|first4=A. R|doi=10.1016/j.taap.2007.06.024}}</ref> Nickel metal is classified as a suspect carcinogen;<ref name="Nickel and nickel compounds" /><ref name="Reg 1272/2008" /><ref name="GHS" /> there is consistency between the absence of increased respiratory cancer risks in workers predominantly exposed to metallic nickel<ref name="Nickel Carcinogenesis in Man" /> and the lack of respiratory tumours in a rat lifetime inhalation carcinogenicity study with nickel metal powder.<ref name="Inhalation carcinogenicity">{{cite journal|pmid=18822311|year=2008|last1=Oller|first1=A. R|title=Inhalation carcinogenicity study with nickel metal powder in Wistar rats|journal=Toxicology and Applied Pharmacology|volume=233|issue=2|pages=262–75|last2=Kirkpatrick|first2=D. T|last3=Radovsky|first3=A|last4=Bates|first4=H. K|doi=10.1016/j.taap.2008.08.017}}</ref> 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.<ref name="Carcinogens" /><ref name="Studies of Nickel Subsulfide" /><ref name="Inhalation carcinogenicity" /><ref>{{cite journal|pmid=12587012|year=1996|title=NTP Toxicology and Carcinogenesis Studies of Nickel Sulfate Hexahydrate (CAS No. 10101-97-0) in F344 Rats and B6C3F1 Mice (Inhalation Studies)|journal=National Toxicology Program Technical Report Series|volume=454|pages=1–380|author1=National Toxicology Program}}</ref> In rat studies, oral ingestion of water-soluble nickel salts can trigger perinatal mortality in pregnant animals.<ref>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.</ref> Whether these effects are relevant to humans is unclear as epidemiological studies of highly exposed female workers have not shown adverse developmental toxicity effects.<ref>{{cite journal|pmid=18655106|year=2008|last1=Vaktskjold|first1=A|title=Maternal nickel exposure and congenital musculoskeletal defects|journal=American Journal of Industrial Medicine|volume=51|issue=11|pages=825–33|last2=Talykova|first2=L. V|last3=Chashchin|first3=V. P|last4=Odland|first4=J. O|last5=Nieboer|first5=E|doi=10.1002/ajim.20609}}</ref>

People can be exposed to nickel in the workplace by inhalation, ingestion, and contact with skin or eye. The [[Organization:Occupational Safety and Health Administration|Occupational Safety and Health Administration]] (OSHA) has set the legal limit ([[Earth:Permissible exposure limit|permissible exposure limit]]) for the workplace at 1&nbsp;mg/m{{sup|3}} per 8-hour workday, excluding nickel carbonyl. The [[Organization:National Institute for Occupational Safety and Health|National Institute for Occupational Safety and Health]] (NIOSH) sets the [[Earth:Recommended exposure limit|recommended exposure limit]] (REL) at 0.015&nbsp;mg/m{{sup|3}} per 8-hour workday. At 10&nbsp;mg/m{{sup|3}}, nickel is immediately dangerous to life and health.<ref>{{cite web|title =NIOSH Pocket Guide to Chemical Hazards – Nickel metal and other compounds (as Ni)|url = https://www.cdc.gov/niosh/npg/npgd0445.html|website =CDC|access-date = 2015-11-20|archive-url = https://web.archive.org/web/20170718164956/https://www.cdc.gov/niosh/npg/npgd0445.html|archive-date = July 18, 2017|url-status = live}}</ref> Nickel carbonyl {{chem2|[Ni(CO)4]}} is an extremely toxic gas. The toxicity of metal carbonyls is a function of both the toxicity of the metal and the off-gassing of [[Chemistry:Carbon monoxide|carbon monoxide]] from the carbonyl functional groups; nickel carbonyl is also explosive in air.<ref>{{cite book|author=Stellman, Jeanne Mager|title=Encyclopaedia of Occupational Health and Safety: Chemical, industries and occupations|url=https://books.google.com/books?id=nDhpLa1rl44C&pg=PT133|access-date=January 9, 2012|date=1998|publisher=International Labour Organization|isbn=978-92-2-109816-4|pages=133–|archive-url=https://web.archive.org/web/20130529043242/http://books.google.com/books?id=nDhpLa1rl44C&pg=PT133|archive-date=May 29, 2013|url-status=live}}</ref><ref>{{cite journal|journal=Clinical Toxicology|date = 1999|volume = 37|issue = 2|pages =239–258| title =Nickel|first1=Donald G.|last1=Barceloux|first2= Donald |last2= Barceloux|doi =10.1081/CLT-100102423|pmid =10382559}}</ref>

[[Biology:Sensitization (immunology)|Sensitized]] persons may show a skin contact allergy to nickel known as a contact [[Medicine:Dermatitis|dermatitis]]. Highly sensitized persons may also react to foods with high nickel content.<ref name="aad" /> Patients with [[Medicine:Dyshidrosis|pompholyx]] may also be sensitive to nickel. Nickel is the top confirmed contact allergen worldwide, partly due to its use in jewelry for pierced ears.<ref>{{cite journal |journal=Contact Dermatitis |date=2007 |volume=57 |issue=5 |pages=287–99 |title= The epidemiology of contact allergy in the general population—prevalence and main findings |author=Thyssen J. P. |author2=Linneberg A. |author3=Menné T.|author4=Johansen J. D. |doi=10.1111/j.1600-0536.2007.01220.x |pmid=17937743|s2cid=44890665 |doi-access=free }}</ref> Nickel allergies affecting pierced ears are often marked by itchy, red skin. Many earrings are now made without nickel or with low-release nickel<ref>[http://www.nipera.org/WorkplaceGuide/ToxicityOfNickelCompounds/NickelAlloys/DermalExposureNickel%20Alloys.aspx Dermal Exposure: Nickel Alloys] {{Webarchive|url=https://web.archive.org/web/20160222055840/http://www.nipera.org/WorkplaceGuide/ToxicityOfNickelCompounds/NickelAlloys/DermalExposureNickel%20Alloys.aspx |date=February 22, 2016 }} Nickel Producers Environmental Research Association (NiPERA), accessed 2016 Feb.11</ref> to address this problem. The amount allowed in products that contact human skin is now regulated by the [[Social:European Union|European 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 a [[Chemistry:Galvanization|galvanic]] reaction.<ref>{{cite journal|first1 = O.|last1 = Nestle|last2=Speidel|first2=H.|last3=Speidel|first3=M. O.|title = High nickel release from 1- and 2-euro coins|journal=Nature|volume = 419|issue = 6903|page = 132|date = 2002|pmid = 12226655|doi = 10.1038/419132a|bibcode = 2002Natur.419..132N |s2cid = 52866209|doi-access = free}}</ref> Nickel was voted Allergen of the Year in 2008 by the American Contact Dermatitis Society.<ref>{{cite web| url =http://www.nickelallergyinformation.com/2008/06/nickel-named-2008-contact-alle.htm| archive-url =https://web.archive.org/web/20090203033929/http://www.nickelallergyinformation.com/2008/06/nickel-named-2008-contact-alle.htm| archive-date =2009-02-03|title = Nickel Named 2008 Contact Allergen of the Year| date = June 3, 2008|author=Dow, Lea |website=Nickel Allergy Information}}</ref> In August 2015, the American 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&nbsp;billion and affects nearly 72.29&nbsp;million people."<ref name="aad">[https://www.aad.org/Forms/Policies/Uploads/PS/PS-Nickel%20Sensitivity.pdf Position Statement on Nickel Sensitivity] {{Webarchive|url=https://web.archive.org/web/20150908083534/https://www.aad.org/Forms/Policies/Uploads/PS/PS-Nickel%20Sensitivity.pdf |date=September 8, 2015 }}. American Academy of Dermatology(August 22, 2015)</ref>

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 intracellular ascorbate. 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.<ref>{{cite journal|first = k.|last = Salnikow|display-authors=4|author2=Donald, S. P. |author3=Bruick, R. K. |author4=Zhitkovich, A. |author5=Phang, J. M. |author6= Kasprzak, K. S. |title = Depletion of intracellular ascorbate by the carcinogenic metal nickel and cobalt results in the induction of hypoxic stress|journal=Journal of Biological Chemistry |volume = 279|pmid = 15271983|doi=10.1074/jbc.M403057200|issue = 39|pages = 40337–44 |date=September 2004|doi-access=free}}</ref><ref>{{cite journal|first1 = K. K.|last1 = Das|last2= Das |first2=S. N. |last3=Dhundasi|first3=S. A.|title = Nickel, its adverse health effects and oxidative stress|journal=Indian Journal of Medical Research |volume = 128|pages = 117–131|date = 2008|pmid=19106437|url = http://www.icmr.nic.in/ijmr/2008/october/1005.pdf|archive-url = https://web.archive.org/web/20090410090734/http://www.icmr.nic.in/ijmr/2008/october/1005.pdf|url-status = dead|archive-date = 2009-04-10| access-date= August 22, 2011 |issue = 4}}</ref>

==Nickel in popular culture==

In the second Oz book, ''The Marvelous Land of Oz'' (by L. Frank Baum, published by Reilly & Britton, 1904), the Tin Woodman states that he has had his tin body nickel-plated.  He is thereafter very careful not to allow his nickel plating to get scratched, nicked, or marred.<ref>The Marvelous Land of Oz, L. Frank Baum.  Chapter: "A Nickel-Plated Emperor", p. 121 and following</ref>

==References==
{{Reflist|30em}}

==External links==
{{Commons|Nickel}}
* [https://www.periodicvideos.com/videos/028.htm Nickel video] from the ''[[Biography:Periodic Videos|Periodic Videos]]'' series (University of Nottingham)
* [https://www.cdc.gov/niosh/npg/npgd0445.html Aluminum] entry (last reviewed October 30, 2019) in the ''NIOSH Pocket Guide to Chemical Hazards'' published by the CDC's [[Organization:National Institute for Occupational Safety and Health|National Institute for Occupational Safety and Health]]
* [https://www.atsdr.cdc.gov/toxprofiles/tp15.pdf Toxicological Profile for Nickel (draft for public comment)] (PDF) (August 2023) – 422-page report from the United States Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry
* [https://www.bbc.com/news/magazine-32749262 The metal that brought you cheap flights], BBC News (2015)

{{Periodic table (navbox)}}
{{Nickel compounds}}

[[Category:Nickel| ]]
[[Category:Chemical elements]]
[[Category:Transition metals]]
[[Category:Dietary minerals]]
[[Category:Ferromagnetic materials]]
[[Category:IARC Group 2B carcinogens]]
[[Category:Native element minerals]]
[[Category:Chemical elements with face-centered cubic structure]]

{{Sourceattribution|Nickel}}