Editing Thallium (section)

==History==
Thallium ([[Greek language|Greek]] {{lang|el|θαλλός}}, {{lang|el-Latn|thallos}}, meaning "a green shoot or twig")<ref>Liddell, Henry George and Scott, Robert (eds.) "[http://perseus.mpiwg-berlin.mpg.de/cgi-bin/resolveform?lookup=qallos&type=begin&lang=greek&searchText=&options=Sort+Results+Alphabetically&.submit=Submit&formentry=1&lang=greek θαλλος] {{Webarchive|url=https://web.archive.org/web/20160415174207/http://perseus.mpiwg-berlin.mpg.de/cgi-bin/resolveform?lookup=qallos&type=begin&lang=greek&searchText=&options=Sort+Results+Alphabetically&.submit=Submit&formentry=1&lang=greek |date=2016-04-15 }}", in ''[[A Greek–English Lexicon]]'', Oxford University Press.</ref> was discovered by [[William Crookes]] and [[Claude Auguste Lamy]], working independently, both using flame spectroscopy (Crookes was first to publish his findings, on March 30, 1861).<ref>* Crookes, William (March 30, 1861) "On the existence of a new element, probably of the sulphur group," ''Chemical News'', vol. 3, [[iarchive:bub_gb_6QcAAAAAMAAJ/page/n197|pp. 193–194]]; reprinted in: {{cite journal |last1=Crookes |first1=William |date=April 1861 |title=XLVI. On the existence of a new element, probably of the sulphur group |url=https://books.google.com/books?id=OhyQnaPXF5QC&pg=RA1-PA301 |url-status=live |journal=Philosophical Magazine |volume=21 |issue=140 |pages=301–305 |doi=10.1080/14786446108643058 |archive-url=https://web.archive.org/web/20140701065556/http://books.google.com/books?id=OhyQnaPXF5QC&pg=RA1-PA301 |archive-date=2014-07-01 |access-date=2016-09-26}}
* Crookes, William (May 18, 1861) "Further remarks on the supposed new metalloid," ''Chemical News'', vol. 3, [[iarchive:bub_gb_6QcAAAAAMAAJ/page/n307|p. 303]].
* Crookes, William (June 19, 1862) "Preliminary researches on thallium," ''Proceedings of the Royal Society of London'', vol. 12, pp. 150–159.
* Lamy, A. (May 16, 1862) "De l'existencè d'un nouveau métal, le thallium," ''Comptes Rendus'', vol. 54, [http://gallica2.bnf.fr/ark:/12148/bpt6k30115.image.r=Comptes+Rendus+Hebdomadaires.f1254.langFR pp. 1255–1262]. {{Webarchive|url=http://arquivo.pt/wayback/20160515195019/http://gallica2.bnf.fr/ark:/12148/bpt6k30115.image.r=Comptes+Rendus+Hebdomadaires.f1254.langFR|date=2016-05-15}}.</ref> The name comes from thallium's bright [[green]] spectral [[emission line]]s<ref>{{cite journal| doi = 10.1021/ed009p2078| title = The discovery of the elements. XIII. Supplementary note on the discovery of thallium| date = 1932| last1 = Weeks| first1 = Mary Elvira|author-link1=Mary Elvira Weeks| journal = Journal of Chemical Education| volume = 9| issue = 12| page = 2078|bibcode = 1932JChEd...9.2078W }}</ref> derived from the Greek 'thallos', meaning a green twig.<ref>{{cite web |title=Thallium – Element information, properties and uses &#124; Periodic Table |url=https://www.rsc.org/periodic-table/element/81/thallium |access-date=2 February 2024 |website=Royal Society of Chemistry}}</ref>

After the publication of the improved method of flame spectroscopy by [[Robert Bunsen]] and [[Gustav Kirchhoff]]<ref>{{cite journal|title = Chemische Analyse durch Spectralbeobachtungen|pages = 337–381|author = G. Kirchhoff|author2 = R. Bunsen|doi = 10.1002/andp.18611890702|journal = [[Annalen der Physik und Chemie]]|volume = 189|issue = 7|date = 1861|bibcode = 1861AnP...189..337K| hdl=2027/hvd.32044080591324 |url = http://archiv.ub.uni-heidelberg.de/volltextserver/15657/1/spektral.pdf|access-date = 2018-04-20|archive-date = 2020-11-14|archive-url = https://web.archive.org/web/20201114043136/http://archiv.ub.uni-heidelberg.de/volltextserver/15657/1/spektral.pdf|url-status = live}}</ref> and the discovery of [[caesium]] and [[rubidium]] in the years 1859 to 1860, flame spectroscopy became an approved method to determine the composition of minerals and chemical products. Crookes and Lamy both started to use the new method. Crookes used it to make spectroscopic determinations for [[tellurium]] on selenium compounds deposited in the [[Lead chamber process|lead chamber]] of a sulfuric acid production plant near [[Abberode|Tilkerode]] in the [[Harz|Harz mountains]]. He had obtained the samples for his research on selenium cyanide from [[August Wilhelm von Hofmann|August Hofmann]] years earlier.<ref>{{cite journal|title = Preliminary Researches on Thallium|first = William|last = Crookes|journal = Proceedings of the Royal Society of London|volume = 12|date = 1862–1863|pages = 150–159|jstor = 112218|doi = 10.1098/rspl.1862.0030|bibcode = 1862RSPS...12..150C|doi-access = free}}</ref><ref>{{cite journal|title = On Thallium|first = William|last = Crookes|journal = Philosophical Transactions of the Royal Society of London|volume = 153|date = 1863|pages = 173–192|jstor = 108794|doi = 10.1098/rstl.1863.0009|url = https://zenodo.org/record/1432438|doi-access = free|access-date = 2019-09-12|archive-date = 2020-03-13|archive-url = https://web.archive.org/web/20200313143322/https://zenodo.org/record/1432438|url-status = live}}</ref> By 1862, Crookes was able to isolate small quantities of the new element and determine the properties of a few compounds.<ref name="DeKosky">{{cite journal|title = Spectroscopy and the Elements in the Late Nineteenth Century: The Work of Sir William Crookes|first = Robert K.|last = DeKosky|journal = The British Journal for the History of Science|volume = 6|issue = 4|date = 1973|pages = 400–423|jstor = 4025503|doi = 10.1017/S0007087400012553|s2cid = 146534210}}</ref> [[Claude-Auguste Lamy]] used a spectrometer that was similar to Crookes' to determine the composition of a selenium-containing substance which was deposited during the production of [[sulfuric acid]] from [[pyrite]]. He also noticed the new green line in the spectra and concluded that a new element was present. Lamy had received this material from the sulfuric acid plant of his friend [[Charles Frédéric Kuhlmann|Frédéric Kuhlmann]] and this by-product was available in large quantities. Lamy started to isolate the new element from that source.<ref>{{cite journal|title = De l'existencè d'un nouveau métal, le thallium|journal = Comptes Rendus|date = 1862|first = Claude-Auguste|last = Lamy|volume = 54|pages = 1255–1262|url = http://gallica2.bnf.fr/ark:/12148/bpt6k30115.image.r=Comptes+Rendus+Hebdomadaires.f1254.langFR|access-date = 2008-11-11|archive-date = 2016-05-15|archive-url = http://arquivo.pt/wayback/20160515195019/http://gallica2.bnf.fr/ark:/12148/bpt6k30115.image.r=Comptes+Rendus+Hebdomadaires.f1254.langFR|url-status = live}}</ref> The fact that Lamy was able to work ample quantities of thallium enabled him to determine the properties of several compounds and in addition he prepared a small ingot of metallic thallium which he prepared by remelting thallium he had obtained by electrolysis of thallium salts.{{citation needed|date=March 2021}}

As both scientists discovered thallium independently and a large part of the work, especially the isolation of the metallic thallium was done by Lamy, Crookes tried to secure his own priority on the work. Lamy was awarded a medal at the International Exhibition in London 1862: ''For the discovery of a new and abundant source of thallium'' and after heavy protest Crookes also received a medal: ''thallium, for the discovery of the new element.'' The controversy between both scientists continued through 1862 and 1863. Most of the discussion ended after Crookes was elected [[Fellow of the Royal Society]] in June 1863.<ref name="James">{{cite journal|title =Of 'Medals and Muddles' the Context of the Discovery of Thallium: William Crookes's Early|first = Frank A. J. L.|last = James|journal =Notes and Records of the Royal Society of London|volume = 39|issue = 1|date = 1984|pages = 65–90|jstor = 531576|doi =10.1098/rsnr.1984.0005|doi-access = free}}</ref><ref name="Murder">{{cite book|title = The Elements of Murder: A History of Poison|chapter = Thallium|first = John|last = Emsley|publisher = Oxford University Press|date = 2006|isbn = 978-0-19-280600-0|chapter-url = https://books.google.com/books?id=BACSR7TXWhoC|pages = 326–327|access-date = 2016-09-26|archive-date = 2020-03-07|archive-url = https://web.archive.org/web/20200307115513/https://books.google.com/books?id=BACSR7TXWhoC|url-status = live}}</ref>
<!-- historic use as rat poison and for night sweat of tuberculosis and for hair removal Thallium Toxicity and the Role of Prussian Blue in Therapy 10.1016/S1383-5742(97)00022-7 10.1007/BF01684859 http://quod.lib.umich.edu/cgi/t/text/text-idx?c=nal;idno=17038117.0238.001-->

The dominant use of thallium was the use as poison for rodents. After several accidents the use as poison was banned in the United States by [[Executive order (United States)|Presidential Executive Order]] 11643 in February 1972. In subsequent years several other countries also banned its use.<ref name="USGS1972">{{cite book|author=Staff of the Nonferrous Metals Division|title=Minerals yearbook metals, minerals, and fuels|date=1972|publisher=United States Geological Survey|volume=1|page=1358|chapter=Thallium|access-date=2010-06-01|chapter-url=http://digicoll.library.wisc.edu/cgi-bin/EcoNatRes/EcoNatRes-idx?type=goto&id=EcoNatRes.MinYB1972v1&page=1358&isize=XL|archive-url=https://web.archive.org/web/20140322013525/http://digicoll.library.wisc.edu/cgi-bin/EcoNatRes/EcoNatRes-idx?type=goto&id=EcoNatRes.MinYB1972v1&page=1358&isize=XL|archive-date=2014-03-22|url-status=live}}</ref>