Editing Nickel (section)

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

Natural nickel is composed of five stable [[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% [[natural abundance]]).{{NUBASE2020|ref}}

[[Nickel-62]] has the highest [[nuclear binding energy|binding energy]] per nucleon of any [[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 [[iron-56|{{chem|56|Fe}}]] and [[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 [[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 [[extinct radionuclide]] [[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 [[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 [[radioisotope]]s have been characterized; the most stable are {{chem|59|Ni}} with [[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 [[Type Ia supernova|type Ia]] [[supernova]]e. The shape of the [[light curve]] of these supernovae at intermediate to late-times corresponds to the decay via [[electron capture]] of {{chem|56|Ni}} to [[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 [[cosmogenic nuclide|cosmogenic]] [[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 [[meteorite]]s and to determine abundances of extraterrestrial dust in ice and [[sediment]]. Nickel-78, with a half-life of 110 milliseconds, is believed an important isotope in [[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 [[proton]]s and 20 [[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 [[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>