Editing Tin (section)

===Isotopes===
{{Main|Isotopes of tin}}
Tin has ten [[stable isotopes]], the [[List of elements by stability of isotopes|greatest number]] of any element. Their mass numbers are 112, 114, 115, 116, 117, 118, 119, 120, 122, and 124. Tin-120 makes up almost a third of all tin. Tin-118 and tin-116 are also common. Tin-115 is the least common stable isotope.<ref>{{Cite web |title=Tin {{!}} NIDC: National Isotope Development Center |url=https://www.isotopes.gov/products/tin |access-date=2025-04-13 |website=www.isotopes.gov}}</ref> The isotopes with even [[mass number]]s have no [[nuclear spin]], while those with odd mass numbers have a nuclear spin of 1/2. It is thought that tin has such a great multitude of stable isotopes because of tin's [[atomic number]] being 50, which is a "[[Magic number (physics)|magic number]]" in nuclear physics.<ref>{{Cite web |title=Testing the Possible Doubly Magic Nature of Tin-100, Researchers Study the Electromagnetic Properties of Indium Isotopes |url=https://www.energy.gov/science/np/articles/testing-possible-doubly-magic-nature-tin-100-researchers-study-electromagnetic |access-date=2025-04-13 |website=Energy.gov |language=en}}</ref><ref>{{Cite journal |last1=Yang |first1=X. F. |last2=Wang |first2=S. J. |last3=Wilkins |first3=S. G. |last4=Ruiz |first4=R. F. Garcia |date=2023-03-01 |title=Laser spectroscopy for the study of exotic nuclei |url=https://linkinghub.elsevier.com/retrieve/pii/S0146641022000631 |journal=Progress in Particle and Nuclear Physics |volume=129 |pages=104005 |doi=10.1016/j.ppnp.2022.104005 |issn=0146-6410|arxiv=2209.15228 }}</ref>

Tin is one of the easiest elements to detect and analyze by [[NMR spectroscopy]], which relies on molecular weight and its [[chemical shift]]s are referenced against [[tetramethyltin]] ({{chem|SnMe|4}}).{{efn|Only hydrogen, fluorine, phosphorus, thallium and xenon are easier to use NMR analysis with for samples containing isotopes at their natural abundance.}}<ref>{{cite web| url = http://www.nyu.edu/cgi-bin/cgiwrap/aj39/NMRmap.cgi| archive-url = https://web.archive.org/web/20110604130629/http://www.nyu.edu/cgi-bin/cgiwrap/aj39/NMRmap.cgi| archive-date = 2011-06-04| title = Interactive NMR Frequency Map| access-date = 2009-05-05| url-status = dead}}</ref>

Of the stable isotopes, tin-115 has a high [[neutron capture cross section]] for fast neutrons, at 30 [[Barn (unit)|barn]]s. Tin-117 has a cross section of 2.3 barns, one order of magnitude smaller, while tin-119 has a slightly smaller cross section of 2.2 barns.<ref name="crosssections">{{Cite journal |last=Sears |first=Varley F. |date=January 1992 |title=Neutron scattering lengths and cross sections |url=http://www.tandfonline.com/doi/abs/10.1080/10448639208218770 |journal=Neutron News |language=en |volume=3 |issue=3 |pages=26–37 |doi=10.1080/10448639208218770 |issn=1044-8632}} Table of cross sections available at NIST: [https://www.ncnr.nist.gov/resources/n-lengths/elements/sn.html Neutron Scattering Lengths and cross sections].</ref> Before these cross sections were well known, it was proposed to use [[solder#Lead-based|tin-lead solder]] as a [[nuclear reactor coolant|coolant]] for [[fast-neutron reactor|fast reactors]] because of its low melting point. Current studies are for lead or [[lead-bismuth eutectic|lead-bismuth]] reactor coolants because both heavy metals are nearly transparent to fast neutrons, with very low capture cross sections.<ref>{{cite web | url=https://www.westinghousenuclear.com/energy-systems/lead-cooled-fast-reactor | title=Westinghouse Nuclear > Energy Systems > Lead-cooled Fast Reactor }}</ref> In order to use a tin or tin-lead coolant, the tin would first have to go through isotopic separation to remove the isotopes with [[even and odd atomic nuclei|odd]] mass number. Combined, these three isotopes make up about 17% of natural tin but represent nearly all of the capture cross section. Of the remaining seven isotopes tin-112 has a capture cross section of 1 barn. The other six isotopes forming 82.7% of natural tin have capture cross sections of 0.3 barns or less, making them effectively transparent to neutrons.<ref name="crosssections" />

Tin has 33 unstable isotopes, ranging in mass number from 98 to 140<!--32 as per [[Isotopes of tin]]; also the inclusive range [98,140] contains 43 integers.-->. The unstable tin isotopes have half-lives of less than a year except for [[tin-126]], which has a [[half-life]] of about 230,000 years. 
Tin-100 and tin-132 are two of the very few [[nuclide]]s with a "[[Double magic|doubly magic]]" nucleus which despite being unstable, as they have very uneven [[neutron–proton ratio]]s, are the endpoints beyond which tin isotopes lighter than tin-100 and heavier than tin-132 are much less stable.<ref>{{cite journal|first = Phil|last = Walker|title = Doubly Magic Discovery of Tin-100|journal = Physics World|volume = 7|issue = June|date = 1994|pages = 28|doi = 10.1088/2058-7058/7/6/24}}</ref> Another 30 [[metastable isomers]] have been identified for tin isotopes between 111 and 131, the most stable being tin-121m, with a half-life of 43.9 years.<ref name="Audi">{{NUBASE 2003}}</ref>

The relative differences in the abundances of tin's stable isotopes can be explained by how they are formed during [[stellar nucleosynthesis]]. Tin-116 through tin-120, along with tin-122, are formed in the [[s-process|''s''-process]] (slow neutron capture) in most [[star]]s which leads to them being the most common tin isotopes, while tin-124 is only formed in the [[r-process|''r''-process]] (rapid neutron capture) in [[supernovae]] and [[neutron star merger]]s. Tin isotopes 115, 117 through 120, and 122 are produced via both the ''s''-process and the ''r''-process,<ref name=Bragagni23>{{cite journal |journal=Geochimica et Cosmochimica Acta |volume=344 |date=2023 |pages=40–58 |title=Mass-independent Sn isotope fractionation and radiogenic 115Sn in chondrites and terrestrial rocks |first1=Alessandro |last1=Bragagni |first2=Frank |last2=Wombacher |first3=Maria |last3=Kirchenbaur |first4=Ninja |last4=Braukmüller |first5=Carsten |last5=Münker |doi=10.1016/j.gca.2023.01.014|doi-access=free }}</ref> The two lightest stable isotopes, tin-112 and tin-114, cannot be made in significant amounts in the ''s''- or ''r''-processes and are among the [[p-nuclei]] whose origins are not well understood. Some theories about their formation include [[proton capture]] and [[photodisintegration]]. Tin-115 might be partially produced in the ''s''-process, both directly and as the daughter of long-lived [[isotopes of indium|indium-115]], and also from the decay of indium-115 produced via the ''r''-process.<ref name=Bragagni23/><ref name="Cameron">{{cite journal|last1 = Cameron|first1 = A. G. W.|year = 1973|title = Abundance of the Elements in the Solar System|url = http://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf|journal = Space Science Reviews|volume = 15|issue = 1|pages = 121–146|doi = 10.1007/BF00172440|bibcode = 1973SSRv...15..121C|s2cid = 120201972|url-status = dead|archive-url = https://web.archive.org/web/20111021030549/http://pubs.giss.nasa.gov/docs/1973/1973_Cameron_1.pdf|archive-date = 2011-10-21}}</ref>