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Author: langbot
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English[en]
Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861, in residues of sulfuric acid production. Both used the newly developed method of flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, from Greek θαλλός, thallós, meaning "green shoot" or "twig", was named by Crookes. It was isolated by both Lamy and Crookes in 1862; Lamy by electrolysis, and Crookes by precipitation and melting of the resultant powder. Crookes exhibited it as a powder precipitated by zinc at the international exhibition, which opened on 1 May that year.[5] Thallium tends to form the +3 and +1 oxidation states. The +3 state resembles that of the other elements in group 13 (boron, aluminium, gallium, indium). However, the +1 state, which is far more prominent in thallium than the elements above it, recalls the chemistry of alkali metals, and thallium(I) ions are found geologically mostly in potassium-based ores, and (when ingested) are handled in many ways like potassium ions (K+) by ion pumps in living cells. Commercially, thallium is produced not from potassium ores, but as a byproduct from refining of heavy-metal sulfide ores. Approximately 65% of thallium production is used in the electronics industry, and the remainder is used in the pharmaceutical industry and in glass manufacturing.[6] It is also used in infrared detectors. The radioisotope thallium-201 (as the soluble chloride TlCl) is used in small amounts as an agent in a nuclear medicine scan, during one type of nuclear cardiac stress test.
Cornish[kw]
Elven gymyk yw thaliom, niver 81 y'n Vosen Beriodek. Y furvell gymyk yw Tl, dhyworth an ger Greka thallos, ow styrya barren las. Nyns eus rann vewoniethel dhodho. Alkan poos gwenonek yw thaliom, hag a greun y'n korf dres termyn, yn arbennek y'n lonethi ha kolon. Yn despit dhe vos gwenonek, usys o thaliom rag bledhynnyow yn medhegel dhe gawsya kelli gols. Agatha Christie a skrifas a-dro dhe bosna thaliom yn hy lyver The Pale Horse. Usys veu thaliom gans governans Irak dhe ladha erbynoryon y'n 1980ow ha 1990ow.. Diskudhys veu thaliom gans William Crookes (1832-1919) yn Loundres yn 1861 pan welas lin gwyrdh yn spektrum trenken sulfurik avlan. Ev a aswonnas bos elven nowydh ena, hag ev a brovyas an hanow thaliom, drefen bos liw y brov flamm avel skyllen. An nessa bledhen Claude-Auguste Lamy (1820-1878) a wrug hwithrans manylys yn Lille, Pow Frynk, hag enyshe an alkan. Wosa dadhel hir, ervirys veu dhe enora an dhew dhiskudher. Diskudhys veu moon thaliom, ha henwys veu crookesit yn 1867. Usys yw thaliom dhe wul gweder arbennek, kellow fototredanek ha sensellow isrudh. Poos atomek thalliom yw 204.38, y boynt teudhi yw 304°C ha'y boynt bryjyon yw 1457°C. Y dhosedh yw 11.9kg an liter. Alkan medhel gwynn-arghansek yw.