Editing Thallium (section)

==Applications==

===Historic uses===
The odorless and tasteless [[Thallium(I) sulfate|thallium sulfate]] was once widely used as rat poison and ant killer. Since 1972 this use has been prohibited in the United States due to safety concerns.<ref name="USGS1972" /><ref name="sl2001" /> Many other countries followed this example. Thallium salts were used in the treatment of [[ringworm]], other [[skin infection]]s and to reduce the [[night sweat]]ing of [[tuberculosis]] patients. This use has been limited due to their narrow [[therapeutic index]], and the development of improved medicines for these conditions.<ref name="CRC" /><ref>{{cite journal|doi = 10.1111/j.1365-2133.1930.tb09395.x|pmid =20774304|pages =59–69|title = The Treatment of Ringworm of The Scalp with Thallium Acetate|date = 1930|issue = 2|last1 = Percival|first1 = G. H.|journal = British Journal of Dermatology|volume = 42|pmc = 2456722}}</ref><ref>{{cite journal|doi = 10.1016/S0378-4274(98)00126-X| pages =1–13|title = Thallium toxicity|date = 1998|last1 = Galvanarzate|first1 = S.|journal = [[Toxicology Letters]]|volume = 99|pmid = 9801025|last2 = Santamarı́a|first2 = A.|issue = 1}}</ref>

===Optics===
[[Thallium(I) bromide]] and [[thallium(I) iodide]] [[crystal]]s have been used as infrared optical materials, because they are harder than other common infrared optics, and because they have transmission at significantly longer wavelengths. The trade name [[KRS-5]] refers to this material.<ref>{{cite journal|pages = 338–346|doi = 10.1364/JOSA.46.000956|title = Refraction and Dispersion of Thallium Bromide Iodide|date = 1956|last1 = Rodney|issue = 11|first1 = William S.|last2 = Malitson|first2 = Irving H.|journal = [[Journal of the Optical Society of America]]|volume = 46|bibcode = 1956JOSA...46..956R}}</ref> [[Thallium(I) oxide]] has been used to manufacture glasses that have a high [[refractive index|index of refraction]]. Combined with sulfur or [[selenium]] and arsenic, thallium has been used in the production of high-[[density]] glasses that have low [[melting point]]s in the range of 125 and 150 Celsius°. These glasses have room-temperature properties that are similar to ordinary glasses and are durable, insoluble in water and have unique [[refractive indices]].<ref>{{cite book|url = https://books.google.com/books?id=jOOSKQHEJdwC&pg=PA52|publisher = [[CRC Press]]|title = Glasses for infrared optics|isbn = 978-0-8493-3785-7|date = 1996|first = Valentina F.|last = Kokorina|access-date = 2016-09-26|archive-date = 2020-03-11|archive-url = https://web.archive.org/web/20200311092514/https://books.google.com/books?id=jOOSKQHEJdwC&pg=PA52|url-status = live}}</ref>

===Electronics===
[[File:Thallium rod corroded.jpg|thumb|right|alt=A heavily pitted, blackish cylindrical rod, with extensive, crumbling brown-and-white corrosion|A corroded thallium rod]]
Thallium(I) sulfide's [[electrical conductivity]] changes with exposure to [[infrared light]], making this compound useful in [[photoresistor]]s.<ref name="CRC">{{cite book |author = Hammond, C. R. |title = The Elements, in Handbook of Chemistry and Physics |edition = 81st |publisher = CRC press |isbn = 978-0-8493-0485-9 |date = 2004-06-29 |url-access = registration |url = https://archive.org/details/crchandbookofche81lide }}</ref> Thallium selenide has been used in [[bolometer]]s for infrared detection.<ref>{{cite journal| bibcode = 1977ApOpt..16.2942N| title = Thallium selenide infrared detector| author = Nayer, P. S| author2 = Hamilton, O.| journal = Appl. Opt.| volume = 16| issue = 11| pages = 2942–4|date =1977| doi = 10.1364/AO.16.002942| pmid = 20174271}}</ref> [[Doping (semiconductor)|Doping]] selenium semiconductors with thallium improves their performance, thus it is used in trace amounts in [[selenium rectifier]]s.<ref name="CRC" /> Another application of thallium doping is the [[sodium iodide]] and [[cesium iodide]] crystals in [[gamma radiation]] detection devices. In these, the sodium iodide crystals are doped with a small amount of thallium to improve their efficiency as [[scintillation (physics)|scintillation]] generators.<ref>{{cite journal|pages =796–810|doi =10.1103/PhysRev.75.796|title =The Detection of Gamma-Rays with Thallium-Activated Sodium Iodide Crystals|date =1949|issue =5|last1 =Hofstadter|first1 =Robert|journal =Physical Review|volume =75|bibcode = 1949PhRv...75..796H }}</ref> Some of the electrodes in [[oxygen analyzer|dissolved oxygen analyzers]] contain thallium.<ref name="sl2001" />

===High-temperature superconductivity===
Research activity with thallium is ongoing to develop [[high-temperature superconductor]]s for such applications as [[magnetic resonance imaging]], storage of magnetic energy, [[linear motor|magnetic propulsion]], and [[electric power generation]] and transmission. The research in applications started after the discovery of the first [[thallium barium calcium copper oxide]] superconductor in 1988.<ref>{{cite journal|journal = Nature|volume = 332|issue = 6160|pages = 138–139|date = 1988|doi = 10.1038/332138a0|title = Bulk superconductivity at 120 K in the Tl–Ca/Ba–Cu–O system|first = Z. Z.|last =Sheng|author2=Hermann A. M. |bibcode=1988Natur.332..138S|s2cid = 30690410}}</ref> Thallium [[cuprate]] superconductors have been discovered that have transition temperatures above 120 K. Some mercury-doped thallium-cuprate superconductors have transition temperatures above 130 K at ambient pressure, nearly as high as the world-record-holding mercury cuprates.<ref>{{cite journal|title=Stabilization of the Tl<sub>2</sub>Ba<sub>2</sub>Ca<sub>2</sub>Cu<sub>3</sub>O<sub>10</sub> superconductor by Hg doping|author=Jia, Y. X.|author2=Lee, C. S.|author3=Zettl, A.|journal=Physica C|volume=234|issue=1–2|pages=24–28|bibcode=1994PhyC..234...24J|doi=10.1016/0921-4534(94)90049-3|date=1994|url=https://zenodo.org/record/1258633|access-date=2019-07-01|archive-date=2020-03-16|archive-url=https://web.archive.org/web/20200316222202/https://zenodo.org/record/1258633|url-status=live}}</ref>

===Nuclear medicine===
Before the widespread application of [[technetium-99m]] in [[nuclear medicine]], the [[radioactive]] isotope [[thallium-201]], with a half-life of 73 hours, was the main substance for [[Myocardial perfusion imaging|nuclear cardiography]]. The nuclide is still used for stress tests for risk stratification in patients with [[coronary artery disease]] (CAD).<ref>{{cite book |title = Essential cardiology: principles and practice |chapter = Nuclear imaging in cardiovascular medicine |first1 = Diwakar |last1 = Jain |first2 = Barry L. |last2 = Zaret |editor = Clive Rosendorff |pages = 221–222 |isbn = 978-1-58829-370-1 |publisher = Humana Press |chapter-url = https://books.google.com/books?id=cY182J9q5NoC&pg=PA222 |date = 2005 |edition = 2nd |access-date = 2016-09-26 |archive-date = 2017-02-19 |archive-url = https://web.archive.org/web/20170219095947/https://books.google.com/books?id=cY182J9q5NoC&pg=PA222 |url-status = live }}</ref><!--<ref>{{cite web|url=http://www.wramc.amedd.army.mil/departments/nuclear/PatientInfo/Thallium.htm|title=Thallium Test] from [[Walter Reed Army Medical Center]}}</ref><ref>[http://www.americanheart.org/presenter.jhtml?identifier=4743 Thallium Stress Test] from the [[American Heart Association]]</ref>--> This isotope of thallium can be generated using a transportable generator, which is similar to the [[technetium-99m generator]].<ref>{{cite journal |title = An integrally shielded transportable generator system for thallium-201 production |journal = International Journal of Applied Radiation and Isotopes |date = 1982 |volume = 33 |issue = 12 |pages = 1439–1443 |last = Lagunas-Solar |first = M. C. |author2 = Little, F. E. |author3 = Goodart, C. D. |url = http://www.medscape.com/medline/abstract/7169272 |doi = 10.1016/0020-708X(82)90183-1 |pmid = 7169272 |access-date = 2006-11-23 |archive-date = 2007-10-12 |archive-url = https://web.archive.org/web/20071012114116/http://www.medscape.com/medline/abstract/7169272 |url-status = live }}</ref> The generator contains [[lead-201]] (half-life 9.33 hours), which decays by [[electron capture]] to thallium-201. The lead-201 can be produced in a [[cyclotron]] by the bombardment of thallium with [[proton]]s or [[deuteron]]s by the (p,3n) and (d,4n) reactions.<ref>[http://www.med.harvard.edu/JPNM/physics/isotopes/Tl/Tl201/prod.html Thallium-201 production] {{Webarchive|url=https://web.archive.org/web/20060913175254/http://www.med.harvard.edu/JPNM/physics/isotopes/Tl/Tl201/prod.html |date=2006-09-13 }} from [[Harvard Medical School]]'s Joint Program in Nuclear Medicine.</ref><ref>{{cite journal | title = Thallium-201 for medical use | url = http://jnm.snmjournals.org/cgi/content/abstract/16/2/151 | pmid = 1110421 | journal = The Journal of Nuclear Medicine | volume = 16 | issue = 2 | pages = 151–5 | date = 1975 | last1 = Lebowitz | first1 = E. | last2 = Greene | first2 = M. W. | last3 = Fairchild | first3 = R. | last4 = Bradley-Moore | first4 = P. R. | last5 = Atkins | first5 = H. L. | last6 = Ansari | first6 = A. N. | last7 = Richards | first7 = P. | last8 = Belgrave | first8 = E. | access-date = 2010-05-13 | archive-date = 2008-10-11 | archive-url = https://web.archive.org/web/20081011152841/http://jnm.snmjournals.org/cgi/content/abstract/16/2/151 | url-status = live }}</ref>

====Thallium stress test====
A thallium stress test is a form of [[scintigraphy]] in which the amount of thallium in tissues correlates with tissue blood supply. Viable cardiac cells have normal [[Na+/K+-ATPase|Na<sup>+</sup>/K<sup>+</sup> ion-exchange pumps]]. The Tl<sup>+</sup> cation binds the K<sup>+</sup> pumps and is transported into the cells. Exercise or [[dipyridamole]] induces widening ([[vasodilation]]) of arteries in the body. This produces [[coronary steal]] by areas where arteries are maximally dilated. Areas of infarct or [[Ischemia|ischemic tissue]] will remain "cold". Pre- and post-stress thallium may indicate areas that will benefit from myocardial [[revascularization]]. Redistribution indicates the existence of coronary steal and the presence of ischemic [[coronary artery disease]].<ref>{{cite book |url=https://books.google.com/books?id=u_A5BSqsb20C&pg=PA100 |page=100 |title=Primary care cardiology |author=Taylor, George J. |publisher=Wiley-Blackwell |date=2004 |isbn=978-1-4051-0386-2 |access-date=2016-09-26 |archive-date=2020-03-12 |archive-url=https://web.archive.org/web/20200312164133/https://books.google.com/books?id=u_A5BSqsb20C&pg=PA100 |url-status=live }}</ref>

===Other uses===
A mercury–thallium alloy, which forms a [[eutectic]] at 8.5% thallium, is reported to freeze at&nbsp;−60&nbsp;°C, some 20&nbsp;°C below the freezing point of mercury. This alloy is used in thermometers and low-temperature switches.<ref name="CRC" /> In organic synthesis, thallium(III) salts, as thallium trinitrate or triacetate, are useful reagents for performing different transformations in aromatics, ketones and olefins, among others.<ref>{{cite journal|pages = 956–960|doi =10.1021/ar50034a003|title = Thallium in organic synthesis|date = 1970|last1 = Taylor|issue = 10|first1 = Edward Curtis|last2 = McKillop|first2 = Alexander|journal = Accounts of Chemical Research|volume = 3}}</ref> Thallium is a constituent of the alloy in the [[anode]] plates of [[magnesium battery|magnesium seawater batteries]].<ref name="sl2001" /> Soluble thallium salts are added to [[gold plating]] baths to increase the speed of plating and to reduce grain size within the gold layer.<ref>{{cite book | url = https://books.google.com/books?id=hDwX3slSvQ4C&pg=PA113 | pages = 113–115 | title = Integrated circuit, hybrid, and multichip module package design guidelines: a focus on reliability | isbn = 978-0-471-59446-8 | author1 = Pecht, Michael | date = 1994-03-01 | publisher = John Wiley & Sons | access-date = 2016-09-26 | archive-date = 2014-07-01 | archive-url = https://web.archive.org/web/20140701063446/http://books.google.com/books?id=hDwX3slSvQ4C&pg=PA113 | url-status = live }}</ref>

A saturated solution of equal parts of thallium(I) [[formate]] (Tl(HCO<sub>2</sub>)) and thallium(I) [[malonate]] (Tl(C<sub>3</sub>H<sub>3</sub>O<sub>4</sub>)) in water is known as [[Clerici solution]]. It is a mobile, odorless liquid which changes from yellowish to colorless upon reducing the concentration of the thallium salts. With a density of 4.25&nbsp;g/cm<sup>3</sup> at 20&nbsp;°C, Clerici solution is one of the heaviest aqueous solutions known. It was used in the 20th century for measuring the density of minerals by the [[Buoyancy|flotation]] method, but its use has discontinued due to the high toxicity and corrosiveness of the solution.<ref name="jahns">{{cite journal|title=Clerici solution for the specific gravity determination of small mineral grains|url=http://www.minsocam.org/ammin/AM24/AM24_116.pdf|volume=24|page=116|date=1939|author=Jahns, R. H.|journal=American Mineralogist|access-date=2009-11-06|archive-date=2012-07-24|archive-url=https://web.archive.org/web/20120724051736/http://www.minsocam.org/ammin/AM24/AM24_116.pdf|url-status=live}}</ref><ref name="b1">{{cite book|url=https://books.google.com/books?id=tfXa13uWiRIC&pg=PA63|pages=63–64|title=Gemmology|author=Peter G. Read|publisher=Butterworth-Heinemann|date=1999|isbn=978-0-7506-4411-2|access-date=2016-09-26|archive-date=2020-03-17|archive-url=https://web.archive.org/web/20200317174113/https://books.google.com/books?id=tfXa13uWiRIC&pg=PA63|url-status=live}}</ref>
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https://books.google.com/books?id=v-04Kn758yIC&pg=PA108
Chemistry of aluminium, gallium, indium, and thallium Von Anthony John Downs Uses of ThalliumSpringer, 19939780751401035
https://books.google.com/books?id=fIu58uZTE-gC&pg=PA390 Structure-property relations in nonferrous metals Von Alan M. Russell, Kok Loong Lee 9780471649526John Wiley and Sons, 2005
http://minerals.usgs.gov/minerals/pubs/commodity/thallium/mcs-2010-thall.pdf
10.1016/j.envint.2004.09.003
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Thallium iodide is frequently used as an additive in [[metal-halide lamp]]s, often together with one or two halides of other metals. It allows optimization of the lamp temperature and color rendering,<ref>{{cite journal|doi=10.1364/JOSA.54.000532|title=Characteristics of Mercury Vapor-Metallic Iodide Arc Lamps|date=1964|last1=Reiling|first1=Gilbert H.|journal=Journal of the Optical Society of America|volume=54|issue=4|page=532|bibcode=1964JOSA...54..532R}}</ref><ref>{{cite journal|doi=10.1364/AO.6.001563|title=The Effect of Thallium Iodide on the Arc Temperature of Hg Discharges|date=1967|last1=Gallo|first1=C. F.|journal=Applied Optics|volume=6|issue=9|pages=1563–5|pmid=20062260|bibcode = 1967ApOpt...6.1563G }}</ref> and shifts the spectral output to the green region, which is useful for underwater lighting.<ref>{{cite news|url=https://www.nytimes.com/1987/08/11/science/undersea-quest-for-giant-squids-and-rare-sharks.html?pagewanted=all&src=pm|title=UNDERSEA QUEST FOR GIANT SQUIDS AND RARE SHARKS|author=Wilford, John Noble|work=The New York Times |date=1987-08-11|access-date=2017-02-13|archive-date=2016-12-20|archive-url=https://web.archive.org/web/20161220102236/http://www.nytimes.com/1987/08/11/science/undersea-quest-for-giant-squids-and-rare-sharks.html?pagewanted=all&src=pm|url-status=live}}</ref>