Editing Indium (section)

==Occurrence==
[[File:S-process-elem-Ag-to-Sb.svg|thumb|upright=1.4|alt=yellow squares with red and blue arrows|The s-process acting in the range from [[silver]] to [[antimony]]]]
Indium is created by the long-lasting (up to thousands of years) [[s-process]] (slow neutron capture) in low-to-medium-mass stars (range in mass between 0.6 and 10 [[solar mass]]es). When a silver-109 atom captures a neutron, it transmutes into silver-110, which then undergoes [[beta decay]] to become cadmium-110. Capturing further neutrons, it becomes cadmium-115, which decays to indium-115 by another [[beta decay]]. This explains why the radioactive isotope is more abundant than the stable one.<ref>{{cite journal|first=A. I. | last= Boothroyd| title = Heavy elements in stars| journal= Science| volume= 314 | issue= 5806| date= 2006 | pages= 1690–1691 | doi= 10.1126/science.1136842 | pmid = 17170281| s2cid= 116938510}}</ref> The stable indium isotope, indium-113, is one of the [[p-nuclei]], the origin of which is not fully understood; although indium-113 is known to be made directly in the s- and [[r-process]]es (rapid neutron capture), and also as the daughter of very long-lived cadmium-113, which has a half-life of about eight [[quadrillion]] years, this cannot account for all indium-113.<ref name="s-contrib">{{cite journal | last1 = Arlandini | first1 = C. | last2 = Käppeler | first2 = F. | last3 = Wisshak | first3 = K. | last4 = Gallino | first4 = R. | last5 = Lugaro | first5 = M. | last6 = Busso | first6 = M. | last7 = Straniero | first7 = O. | year = 1999| title = Neutron Capture in Low-Mass Asymptotic Giant Branch Stars: Cross Sections and Abundance Signatures. | journal = The Astrophysical Journal | volume = 525 | issue = 2 | pages = 886–900 | doi = 10.1086/307938 | arxiv = astro-ph/9906266 | bibcode = 1999ApJ...525..886A | s2cid = 10847307 }}</ref><ref name="r-contrib">{{cite journal | last1 = Zs | last2 = Käppeler | first2 = F. | last3 = Theis | first3 = C. | last4 = Belgya | first4 = T. | last5 = Yates | first5 = S. W. | year = 1994| title = Nucleosynthesis in the Cd-In-Sn region. | journal = The Astrophysical Journal | volume = 426 | pages = 357–365 | doi = 10.1086/174071 | bibcode = 1994ApJ...426..357N }}</ref>

Indium is the [[Abundance of elements in Earth's crust|68th most abundant element in Earth's crust]] at approximately 50 [[parts per billion|ppb]]. This is similar to the crustal abundance of [[silver]], [[bismuth]] and [[Mercury (element)|mercury]]. It very rarely forms its own minerals, or occurs in elemental form. Fewer than 10 indium minerals such as [[roquesite]] (CuInS<sub>2</sub>) are known, and none occur at sufficient concentrations for economic extraction.<ref name="Frenzel-2016">{{Cite journal|url=https://www.researchgate.net/publication/309583931|title=The distribution of gallium, germanium and indium in conventional and non-conventional resources - Implications for global availability (PDF Download Available)|website=ResearchGate|doi=10.13140/rg.2.2.20956.18564|access-date=2017-06-02|year=2016|last1=Frenzel|first1=Max|archive-date=2018-10-06|archive-url=https://web.archive.org/web/20181006235214/https://www.researchgate.net/publication/309583931|url-status=live}}</ref> Instead, indium is usually a trace constituent of more common ore minerals, such as [[sphalerite]] and [[chalcopyrite]].<ref>{{Cite journal|last1=Frenzel|first1=Max|last2=Hirsch|first2=Tamino|last3=Gutzmer|first3=Jens|date=July 2016|title=Gallium, germanium, indium, and other trace and minor elements in sphalerite as a function of deposit type — A meta-analysis|journal=Ore Geology Reviews|volume=76|pages=52–78|doi=10.1016/j.oregeorev.2015.12.017|bibcode=2016OGRv...76...52F }}</ref><ref>{{Cite journal|last1=Bachmann|first1=Kai|last2=Frenzel|first2=Max|last3=Krause|first3=Joachim|last4=Gutzmer|first4=Jens|date=June 2017|title=Advanced Identification and Quantification of In-Bearing Minerals by Scanning Electron Microscope-Based Image Analysis|journal=Microscopy and Microanalysis|volume=23|issue=3|pages=527–537|doi=10.1017/S1431927617000460|pmid=28464970|issn=1431-9276|bibcode=2017MiMic..23..527B|s2cid=6751828}}</ref> From these, it can be extracted as a [[by-product]] during smelting.<ref name="Frenzel-2017">{{Cite journal|last1=Frenzel|first1=Max|last2=Mikolajczak|first2=Claire|last3=Reuter|first3=Markus A.|last4=Gutzmer|first4=Jens|date=June 2017|title=Quantifying the relative availability of high-tech by-product metals – The cases of gallium, germanium and indium|journal=Resources Policy|volume=52|pages=327–335|doi=10.1016/j.resourpol.2017.04.008|bibcode=2017RePol..52..327F |doi-access=free}}</ref> While the enrichment of indium in these deposits is high relative to its crustal abundance, it is insufficient, at current prices, to support extraction of indium as the main product.<ref name="Frenzel-2016" />

Different estimates exist of the amounts of indium contained within the ores of other metals.<ref name="USGSCS2007">{{cite web|url=http://minerals.usgs.gov/minerals/pubs/commodity/indium/indiumcs07.pdf|title=Mineral Commodities Summary 2007: Indium|publisher=United States Geological Survey|access-date=2007-12-26|archive-date=2008-05-09|archive-url=https://web.archive.org/web/20080509184325/http://minerals.usgs.gov/minerals/pubs/commodity/indium/indiumcs07.pdf|url-status=live}}</ref><ref>{{Cite journal|last1=Werner|first1=T. T.|last2=Mudd|first2=G. M.|last3=Jowitt|first3=S. M.|date=2015-10-02|title=Indium: key issues in assessing mineral resources and long-term supply from recycling|journal=Applied Earth Science|volume=124|issue=4|pages=213–226|doi=10.1179/1743275815Y.0000000007|bibcode=2015ApEaS.124..213W |s2cid=128555024|issn=0371-7453}}</ref> However, these amounts are not extractable without mining of the host materials (see Production and availability). Thus, the availability of indium is fundamentally determined by the ''rate'' at which these ores are extracted, and not their absolute amount. This is an aspect that is often forgotten in the current debate, e.g. by the Graedel group at Yale in their criticality assessments,<ref>{{Cite journal|last1=Graedel|first1=T. E.|last2=Barr|first2=Rachel|last3=Chandler|first3=Chelsea|last4=Chase|first4=Thomas|last5=Choi|first5=Joanne|last6=Christoffersen|first6=Lee|last7=Friedlander|first7=Elizabeth|last8=Henly|first8=Claire|last9=Jun|first9=Christine|date=2012-01-17|title=Methodology of Metal Criticality Determination|journal=Environmental Science & Technology|volume=46|issue=2|pages=1063–1070|doi=10.1021/es203534z|pmid=22191617|issn=0013-936X|bibcode=2012EnST...46.1063G}}</ref> explaining the paradoxically low depletion times some studies cite.<ref>{{Cite journal|last1=Harper|first1=E. M.|last2=Kavlak|first2=Goksin|last3=Burmeister|first3=Lara|last4=Eckelman|first4=Matthew J.|last5=Erbis|first5=Serkan|last6=Sebastian Espinoza|first6=Vicente|last7=Nuss|first7=Philip|last8=Graedel|first8=T. E.|date=2015-08-01|title=Criticality of the Geological Zinc, Tin, and Lead Family|journal=Journal of Industrial Ecology|volume=19|issue=4|pages=628–644|doi=10.1111/jiec.12213|bibcode=2015JInEc..19..628H |s2cid=153380535|issn=1530-9290|url=http://hdl.handle.net/10.1111/jiec.2015.19.issue-4}}{{Dead link|date=October 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name="Frenzel-2017" />