Editing Gallium (section)

==Applications==
Semiconductor applications dominate the commercial demand for gallium, accounting for 98% of the total. The next major application is for [[gadolinium gallium garnet]]s.<ref name="Ullmann">Greber, J. F. (2012) "Gallium and Gallium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, {{doi|10.1002/14356007.a12_163}}.</ref> As of 2022, 44% of world use went to light fixtures and 36% to integrated circuits, with smaller shares equal to ~7% going to photovoltaics and magnets each.<ref>{{Cite web |title=Global Gallium consumption distribution by end-use |url=https://www.statista.com/statistics/605987/distribution-of-world-gallium-consumption-by-end-use/ |access-date=2024-12-20 |website=Statista |language=en}}</ref>

===Semiconductors===
[[File:Blue LED and Reflection.jpg|thumb|Gallium-based blue LEDs]]
Extremely high-purity (>99.9999%) gallium is commercially available to serve the [[semiconductor]] industry. [[Gallium arsenide]] (GaAs) and [[gallium nitride]] (GaN) used in electronic components represented about 98% of the gallium consumption in the United States in 2007. About 66% of semiconductor gallium is used in the U.S. in integrated circuits (mostly gallium arsenide), such as the manufacture of ultra-high-speed logic chips and [[MESFET]]s for low-noise microwave preamplifiers in cell phones. About 20% of this gallium is used in [[optoelectronic]]s.<ref name="USGSCS2008">{{cite web|url= http://minerals.usgs.gov/minerals/pubs/commodity/gallium/mcs-2008-galli.pdf |archive-url=https://web.archive.org/web/20080514204029/http://minerals.usgs.gov/minerals/pubs/commodity/gallium/mcs-2008-galli.pdf |archive-date=14 May 2008 |url-status=live|title= Mineral Commodity Summary 2006: Gallium|publisher= United States Geological Survey|access-date= 20 November 2008|first= Deborah A.|last= Kramer}}</ref>

Worldwide, gallium arsenide makes up 95% of the annual global gallium consumption.<ref name="Moskalyk" /> It amounted to $7.5&nbsp;billion in 2016, with 53% originating from cell phones, 27% from wireless communications, and the rest from automotive, consumer, fiber-optic, and military applications. The recent increase in GaAs consumption is mostly related to the emergence of [[3G]] and [[4G]] [[smartphone]]s, which employ up to 10 times the amount of GaAs in older models.<ref name="usgs2018" />

Gallium arsenide and gallium nitride can also be found in a variety of optoelectronic devices which had a market share of $15.3&nbsp;billion in 2015 and $18.5&nbsp;billion in 2016.<ref name="usgs2018" /> [[Aluminium gallium arsenide]] (AlGaAs) is used in high-power infrared laser diodes. The semiconductors gallium nitride and [[indium gallium nitride]] are used in blue and violet optoelectronic devices, mostly [[laser diode]]s and [[light-emitting diode]]s. For example, gallium nitride 405&nbsp;nm diode lasers are used as a violet light source for higher-density [[Blu-ray Disc]] compact data disc drives.<ref>{{cite book |url= https://books.google.com/books?id=pVkhYTzdXgoC&pg=PA150 |pages= 150–151 |title= Advances in Semiconductor Lasers |isbn= 978-0-12-391066-0 |last1= Coleman |first1= James J. |last2= Jagadish |first2= Chennupati |last3= Catrina Bryce |first3= A. |date= 2 May 2012|publisher= Academic Press }}</ref>

Other major applications of gallium nitride are cable television transmission, commercial wireless infrastructure, power electronics, and satellites. The GaN radio frequency device market alone was estimated at $370&nbsp;million in 2016 and $420&nbsp;million in 2016.<ref name="usgs2018" />

[[Multijunction photovoltaic cell]]s, developed for [[satellite]] power applications, are made by [[molecular-beam epitaxy]] or [[metalorganic vapour-phase epitaxy]] of [[thin film]]s of gallium arsenide, [[indium gallium phosphide]], or [[indium gallium arsenide]]. The [[Mars Exploration Rover]]s and several satellites use triple-junction gallium arsenide on germanium cells.<ref>{{cite journal|doi= 10.1016/S0094-5765(02)00287-4 |title= The performance of gallium arsenide/germanium solar cells at the Martian surface |date= 2004 |first= D.|last= Crisp |author2= Pathare, A. |author3=Ewell, R. C. |journal= Acta Astronautica |volume= 54|pages= 83–101|issue= 2|bibcode= 2004AcAau..54...83C}}</ref> Gallium is also a component in [[photovoltaic]] compounds (such as copper indium gallium selenium sulfide {{chem2|Cu(In,Ga)(Se,S)2}}) used in solar panels as a cost-efficient alternative to [[crystalline silicon]].<ref>{{cite journal |title= Material and device properties of single-phase Cu(In,Ga)(Se,S)<sub>2</sub> alloys prepared by selenization/sulfurization of metallic alloys |first= V.|last= Alberts |author2= Titus J. |author3= Birkmire R. W. |journal= Thin Solid Films |volume= 451–452|pages= 207–211 |date= 2003 |doi= 10.1016/j.tsf.2003.10.092|bibcode= 2004TSF...451..207A}}</ref>

===Galinstan and other alloys===
[[File:Galinstan on glass.jpg|thumb|Galinstan easily wetting a piece of ordinary glass]]
[[File:Gallium alloy 3D prints (26519727708).jpg|thumb|Owing to their low melting points, gallium and its alloys can be shaped into various 3D forms using [[3D printing]] and [[additive manufacturing]].]]
Gallium readily [[alloy]]s with most metals, and is used as an ingredient in [[low-melting alloy]]s. The nearly [[eutectic]] alloy of gallium, [[indium]], and [[tin]] is a room temperature liquid used in medical thermometers. This alloy, with the trade-name ''[[Galinstan]]'' (with the "-stan" referring to the tin, {{Lang|la|stannum}} in Latin), has a low melting point of −19&nbsp;°C (−2.2&nbsp;°F).<ref>{{cite journal|doi=10.1007/s00216-005-0069-7|date=Nov 2005|author=Surmann, P|author2=Zeyat, H|title=Voltammetric analysis using a self-renewable non-mercury electrode|volume=383|issue=6|pages=1009–13|issn=1618-2642|pmid=16228199|journal=Analytical and Bioanalytical Chemistry|s2cid=22732411}}</ref> It has been suggested that this family of alloys could also be used to cool computer chips in place of water, and is often used as a replacement for [[Thermal grease|thermal paste]] in high-performance computing.<ref>{{cite web|title= Hot chips chilled with liquid metal|date= 5 May 2005|first= Will|last= Knight|url= https://www.newscientist.com/article.ns?id=dn7348|access-date= 20 November 2008|archive-url= https://web.archive.org/web/20070211083832/https://www.newscientist.com/article.ns?id=dn7348|archive-date= 11 February 2007}}</ref><ref>{{Cite web|url=https://domino.research.ibm.com/library/cyberdig.nsf/papers/AD9B6F5D509CEB3D85257372004FC2C3/$File/rc24372.pdf|title=High Performance Liquid Metal Thermal Interface for Large Volume Production|last=Martin|first=Yves|access-date=20 November 2019|archive-date=9 March 2020|archive-url=https://web.archive.org/web/20200309123838/https://domino.research.ibm.com/library/cyberdig.nsf/papers/AD9B6F5D509CEB3D85257372004FC2C3/$File/rc24372.pdf|url-status=dead}}</ref> Gallium alloys have been evaluated as substitutes for mercury [[dental amalgam]]s, but these materials have yet to see wide acceptance.  Liquid alloys containing mostly gallium and indium have been found to precipitate gaseous CO<sub>2</sub> into solid carbon and are being researched as potential methodologies for [[Carbon capture and storage|carbon capture]] and possibly [[Carbon dioxide removal|carbon removal]].<ref>{{Cite web |title=Technology solidifies carbon dioxide – ASME |url=https://www.asme.org/topics-resources/content/gallium-turns-co2-into-solid |access-date=5 September 2022 |website=www.asme.org |language=en}}</ref><ref>{{Cite web |title=New way to turn carbon dioxide into coal could 'rewind the emissions clock' |url=https://www.science.org/content/article/liquid-metal-catalyst-turns-carbon-dioxide-coal |access-date=5 September 2022 |website=www.science.org |language=en}}</ref>

Because gallium [[wetting|wets]] glass or [[porcelain]], gallium can be used to create brilliant [[mirror]]s. When the wetting action of gallium-alloys is not desired (as in Galinstan glass thermometers), the glass must be protected with a transparent layer of [[gallium(III) oxide]].<ref>{{cite book |url= https://books.google.com/books?id=2EZSAAAAMAAJ|title= Liquid-metals handbook|publisher= U.S. Govt. Print. Off.|date= 1954 |author= United States. Office of Naval Research. Committee on the Basic Properties of Liquid Metals, U.S. Atomic Energy Commission|page= 128}}</ref>

Due to their high [[surface tension]] and [[fluid mechanics|deformability]],<ref>{{cite journal |last1=Khan |first1=Mohammad Rashed |last2=Eaker |first2=Collin B. |last3=Bowden |first3=Edmond F. |last4=Dickey |first4=Michael D. |title=Giant and switchable surface activity of liquid metal via surface oxidation |journal=Proceedings of the National Academy of Sciences |date=30 September 2014 |volume=111 |issue=39 |pages=14047–14051 |doi=10.1073/pnas.1412227111 |doi-access=free |pmid=25228767 |bibcode=2014PNAS..11114047K |pmc=4191764 }}</ref> gallium-based liquid metals can be used to create [[actuator]]s by controlling the surface tension.<ref>{{cite journal |last1=Russell |first1=Loren |last2=Wissman |first2=James |last3=Majidi |first3=Carmel |title=Liquid metal actuator driven by electrochemical manipulation of surface tension |journal=Applied Physics Letters |date=18 December 2017 |volume=111 |issue=25 |doi=10.1063/1.4999113 |bibcode=2017ApPhL.111y4101R |doi-access=free }}</ref><ref>{{cite journal |last1=Liao |first1=Jiahe |last2=Majidi |first2=Carmel |title=Soft actuators by electrochemical oxidation of liquid metal surfaces |journal=Soft Matter |date=2021 |volume=17 |issue=7 |pages=1921–1928 |doi=10.1039/D0SM01851A |pmid=33427274 |bibcode=2021SMat...17.1921L }}</ref><ref>{{cite journal |last1=Liao |first1=Jiahe |last2=Majidi |first2=Carmel |title=Muscle-Inspired Linear Actuators by Electrochemical Oxidation of Liquid Metal Bridges |journal=Advanced Science |date=September 2022 |volume=9 |issue=26 |pages=e2201963 |doi=10.1002/advs.202201963 |pmid=35863909 |pmc=9475532 }}</ref> Researchers have demonstrated the potentials of using liquid metal actuators as [[artificial muscles|artificial muscle]] in robotic actuation.<ref>{{cite journal |last1=Liao |first1=Jiahe |last2=Majidi |first2=Carmel |last3=Sitti |first3=Metin |title=Liquid Metal Actuators: A Comparative Analysis of Surface Tension Controlled Actuation |journal=Advanced Materials |date=January 2024 |volume=36 |issue=1 |pages=e2300560 |doi=10.1002/adma.202300560 |pmid=37358049 |bibcode=2024AdM....3600560L |hdl=20.500.11850/641439 |hdl-access=free }}</ref><ref>{{cite thesis |last= Liao|first= Jiahe|date= 2022|title= Liquid metal actuators|url= https://kilthub.cmu.edu/authors/Jiahe_Liao/4939036|degree= Ph.D.|publisher= Carnegie Mellon University}}</ref>

The [[plutonium]] used in [[plutonium pit|nuclear weapon pits]] is stabilized in the [[allotropes of plutonium|δ phase]] and made machinable by [[Plutonium–gallium alloy|alloying with gallium]].<ref>{{cite web|author=Sublette, Cary |title=Section 6.2.2.1 |date=9 September 2001 |work=Nuclear Weapons FAQ |url=http://nuclearweaponarchive.org/Nwfaq/Nfaq6.html#nfaq6.2 |access-date=24 January 2008}}</ref><ref>{{cite journal|title= Thermochemical Behavior of Gallium in Weapons-Material-Derived Mixed-Oxide Light Water Reactor (LWR) Fuel|first= Theodore M.|last= Besmann|journal= Journal of the American Ceramic Society|volume= 81|pages= 3071–3076 |date= 2005 |doi= 10.1111/j.1151-2916.1998.tb02740.x |issue= 12|url= https://zenodo.org/record/1230603}}</ref>

===Biomedical applications===
Although gallium has no natural function in biology, gallium ions interact with processes in the body in a manner similar to [[Ferric#Ferric iron and life|iron(III)]]. Because these processes include [[inflammation]], a marker for many disease states, several gallium salts are used (or are in development) as [[pharmaceutical drug|pharmaceuticals]] and [[radiopharmacology|radiopharmaceuticals]] in medicine. Interest in the anticancer properties of gallium emerged when it was discovered that <sup>67</sup>Ga(III) citrate injected in tumor-bearing animals localized to sites of tumor. Clinical trials have shown gallium nitrate to have antineoplastic activity against non-Hodgkin's lymphoma and urothelial cancers. A new generation of gallium-ligand complexes such as tris(8-quinolinolato)gallium(III) (KP46) and gallium maltolate has emerged.<ref>{{cite book |doi=10.1515/9783110470734-016 |chapter=16. Copper Complexes in Cancer Therapy |title=Metallo-Drugs: Development and Action of Anticancer Agents |date=2018 |last1=Denoyer |first1=Delphine |last2=Clatworthy |first2=Sharnel A. S. |last3=Cater |first3=Michael A. |series=Metal Ions in Life Sciences |volume=18 |pages=469–506 |pmid=29394029 |isbn=978-3-11-047073-4 }}</ref> [[Gallium nitrate]] (brand name Ganite) has been used as an intravenous pharmaceutical to treat [[hypercalcemia]] associated with tumor [[metastasis]] to bones. Gallium is thought to interfere with [[osteoclast]] function, and the therapy may be effective when other treatments have failed.<ref>{{cite web|url=http://www.cancer.org/docroot/CDG/content/CDG_gallium_nitrate.asp |title=gallium nitrate |url-status=dead |access-date=7 July 2009 |archive-url=https://web.archive.org/web/20090608234315/http://www.cancer.org/docroot/CDG/content/CDG_gallium_nitrate.asp |archive-date=8 June 2009}}</ref> [[Gallium maltolate]], an oral, highly absorbable form of gallium(III) ion, is an anti-proliferative to pathologically proliferating cells, particularly cancer cells and some bacteria that accept it in place of ferric iron (Fe<sup>3+</sup>). Researchers are conducting clinical and preclinical trials on this compound as a potential treatment for a number of cancers, infectious diseases, and inflammatory diseases.<ref>{{cite journal|author= Bernstein, L. R.|author2= Tanner, T.|author3= Godfrey, C.|author4= Noll, B.|name-list-style= amp |title= Chemistry and Pharmacokinetics of Gallium Maltolate, a Compound With High Oral Gallium Bioavailability|journal= Metal-Based Drugs|date= 2000|volume= 7 |issue= 1 |pmid= 18475921|pmc= 2365198 |doi= 10.1155/MBD.2000.33|pages= 33–47|doi-access= free}}</ref>

When gallium ions are mistakenly taken up in place of iron(III) by bacteria such as ''[[Pseudomonas]]'', the ions interfere with respiration, and the bacteria die. This happens because iron is redox-active, allowing the transfer of electrons during respiration, while gallium is redox-inactive.<ref>{{cite web|url= http://www.infoniac.com/health-fitness/trojan-gallium.html|title= A Trojan-horse strategy selected to fight bacteria|date= 16 March 2007|publisher= INFOniac.com |access-date= 20 November 2008}}</ref><ref>{{cite web|url= http://www.medpagetoday.com/InfectiousDisease/GeneralInfectiousDisease/tb/5266|title= Gallium May Have Antibiotic-Like Properties|first= Michael|last= Smith|publisher= MedPage Today|date= 16 March 2007|access-date= 20 November 2008}}</ref>

A complex [[amine]]-[[phenol]] Ga(III) compound MR045 is selectively toxic to parasites resistant to [[chloroquine]], a common drug against [[malaria]]. Both the Ga(III) complex and chloroquine act by inhibiting crystallization of [[hemozoin]], a disposal product formed from the digestion of blood by the parasites.<ref>{{cite journal|pmid=9045684|journal=J. Biol. Chem. |date=1997 |volume=272|issue=10|pages=6567–72|title= Probing the chloroquine resistance locus of Plasmodium falciparum with a novel class of multidentate metal(III) coordination complexes|author=Goldberg D. E.|author2= Sharma V.|author3=Oksman A.|author4=Gluzman I. Y.|author5=Wellems T. E.|author6=Piwnica-Worms D.|doi=10.1074/jbc.272.10.6567|s2cid=3408513 |doi-access=free }}</ref><ref>{{cite book|doi=10.1007/978-3-642-13185-1_7|chapter=Bioorganometallic Chemistry and Malaria|title=Medicinal Organometallic Chemistry|series=Topics in Organometallic Chemistry|date=2010|last1=Biot|first1=Christophe|last2=Dive|first2=Daniel|isbn=978-3-642-13184-4|volume=32|page=155|s2cid=85940061}}</ref>

====Radiogallium salts====
[[Gallium-67]] [[Salt (chemistry)|salts]] such as gallium [[citrate]] and gallium [[nitrate]] are used as [[radiopharmaceutical]] agents in the [[nuclear medicine]] imaging known as [[gallium scan]]. The [[radionuclide|radioactive isotope]] <sup>67</sup>Ga is used, and the compound or salt of gallium is unimportant. The body handles Ga<sup>3+</sup> in many ways as though it were Fe<sup>3+</sup>, and the ion is bound (and concentrates) in areas of inflammation, such as infection, and in areas of rapid cell division. This allows such sites to be imaged by nuclear scan techniques.<ref name="Nordberg" />

[[Gallium-68]], a positron emitter with a half-life of 68 min, is now used as a diagnostic radionuclide in PET-CT when linked to pharmaceutical preparations such as [[DOTATOC]], a [[somatostatin]] analogue used for [[neuroendocrine tumors]] investigation, and [[DOTA-TATE]], a newer one, used for neuroendocrine [[metastasis]] and lung neuroendocrine cancer, such as certain types of ''[[microcytoma]]''. Gallium-68's preparation as a pharmaceutical is chemical, and the radionuclide is extracted by [[elution]] from germanium-68, a [[synthetic radioisotope]] of [[germanium]], in [[gallium-68 generator]]s.<ref>{{cite journal |last1=Banerjee |first1=Sangeeta Ray |last2=Pomper |first2=Martin G. |date=June 2013 |title=Clinical Applications of Gallium-68 |pmc=3664132 |journal=Appl. Radiat. Isot. |volume=76 |pages=2–13 |doi=10.1016/j.apradiso.2013.01.039 |pmid=23522791|bibcode=2013AppRI..76....2B }}</ref>

===Other uses===
'''Neutrino detection''': Gallium is used for [[neutrino detection]]. Possibly the largest amount of pure gallium ever collected in a single location is the Gallium-Germanium Neutrino Telescope used by the [[SAGE (Soviet-American Gallium Experiment)|SAGE experiment]] at the [[Baksan Neutrino Observatory]] in Russia. This detector contains 55–57 tonnes (~9 cubic metres) of liquid gallium.<ref>{{cite web|url= http://ewi.npl.washington.edu/sage/|title= Russian American Gallium Experiment|date= 19 October 2001|access-date= 24 June 2009|archive-url= https://web.archive.org/web/20100705232418/http://ewi.npl.washington.edu/SAGE/|archive-date= 5 July 2010|url-status= dead}}</ref> Another experiment was the [[GALLEX]] neutrino detector operated in the early 1990s in an Italian mountain tunnel. The detector contained 12.2 tons of watered gallium-71. [[Solar neutrino]]s caused a few atoms of <sup>71</sup>Ga to become radioactive <sup>71</sup>[[germanium|Ge]], which were detected. This experiment showed that the solar neutrino flux is 40% less than theory predicted. This deficit ([[solar neutrino problem]]) was not explained until better solar neutrino detectors and theories were constructed (see [[Sudbury Neutrino Observatory|SNO]]).<ref>{{cite web|url= http://wwwlapp.in2p3.fr/neutrinos/anexp.html#gallex|title= Neutrino Detectors Experiments: GALLEX|date= 26 June 1999|access-date= 20 November 2008}}</ref>

'''Ion source''': Gallium is also used as a [[liquid metal ion source]] for a [[focused ion beam]]. For example, a focused gallium-ion beam was used to create the world's smallest book, ''[[Teeny Ted from Turnip Town]]''.<ref name="pr">[https://www.sfu.ca/mediapr/news_releases/archives/news04110701.htm "Nano lab produces world's smallest book"] {{Webarchive|url=https://web.archive.org/web/20151013010453/https://www.sfu.ca/mediapr/news_releases/archives/news04110701.htm |date=13 October 2015 }}. Simon Fraser University. 11 April 2007. Retrieved 31 January 2013.</ref>

'''Lubricants''': Gallium serves as an additive in [[glide wax]] for skis and other low-friction surface materials.<ref>{{cite patent |inventor1-last=Sugimura |inventor1-first=Kentaro |inventor2-last=Hasimoto |inventor2-first=Shoji |inventor3-last=Ono |inventor3-first=Takayuki |title=Use of a synthetic resin composition containing gallium particles in the glide surfacing material of skis and other applications |issue-date=1995 |patent-number=5069803 |country-code= US}}</ref>

'''Flexible electronics''': Materials scientists speculate that the properties of gallium could make it suitable for the development of flexible and wearable devices.<ref name="Kleiner">{{cite journal |last1=Kleiner |first1=Kurt |title=Gallium: The liquid metal that could transform soft electronics |journal=Knowable Magazine |date=3 May 2022 |doi=10.1146/knowable-050322-2  |doi-access=free |url=https://knowablemagazine.org/article/technology/2022/gallium-liquid-metal-could-transform-soft-electronics |access-date=31 May 2022}}</ref><ref name="Tang">{{cite journal |last1=Tang |first1=Shi-Yang |last2=Tabor |first2=Christopher |last3=Kalantar-Zadeh |first3=Kourosh |last4=Dickey |first4=Michael D. |title=Gallium Liquid Metal: The Devil's Elixir |journal=Annual Review of Materials Research |date=26 July 2021 |volume=51 |issue=1 |pages=381–408 |doi=10.1146/annurev-matsci-080819-125403 |bibcode=2021AnRMS..51..381T |s2cid=236566966 |issn=1531-7331|doi-access=free }}</ref>

'''Hydrogen generation''': Gallium disrupts the [[Passivation (chemistry)|protective oxide layer]] on aluminium, allowing water to react with the aluminium in [[AlGa]] to produce hydrogen gas.<ref name="Amberchan 2022">{{cite journal |last1=Amberchan |first1=Gabriella |last2=Lopez |first2=Isai |last3=Ehlke |first3=Beatriz |last4=Barnett |first4=Jeremy |last5=Bao |first5=Neo Y. |last6=Allen |first6=A’Lester |last7=Singaram |first7=Bakthan |last8=Oliver |first8=Scott R. J. |title=Aluminum Nanoparticles from a Ga–Al Composite for Water Splitting and Hydrogen Generation |journal=ACS Applied Nano Materials |date=25 February 2022 |volume=5 |issue=2 |pages=2636–2643 |doi=10.1021/acsanm.1c04331 }}</ref>

'''Humor''': A well-known [[practical joke]] among chemists is to fashion gallium spoons and use them to serve tea to unsuspecting guests, since gallium has a similar appearance to its lighter homolog aluminium. The spoons then melt in the hot tea.<ref name="Sam Kean2010">{{cite book|author=Kean, Sam|title=The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements|url=https://archive.org/details/disappearingspoo0000kean|date=2010|publisher=Little, Brown and Company|location=Boston|isbn=978-0-316-05164-4|url-access=registration}}</ref>