Editing Actinide (section)

=== From actinium to uranium ===
[[File:Enrico Fermi 1943-49.jpg|thumb|left|[[Enrico Fermi]] suggested the existence of transuranium elements in 1934.]]

[[Uranium]] and [[thorium]] were the first actinides [[discovery of the chemical elements|discovered]]. Uranium was identified in 1789 by the German chemist [[Martin Heinrich Klaproth]] in [[Uraninite|pitchblende]] ore. He named it after the planet [[Uranus (planet)|Uranus]],<ref name=g1250 /> which had been discovered eight years earlier. Klaproth was able to precipitate a yellow compound (likely [[sodium diuranate]]) by dissolving [[pitchblende]] in [[nitric acid]] and neutralizing the solution with [[sodium hydroxide]]. He then reduced the obtained yellow powder with charcoal, and extracted a black substance that he mistook for metal.<ref>{{cite journal|title=Chemische Untersuchung des Uranits, einer neuentdeckten metallischen Substanz|author-link= Martin Heinrich Klaproth|author=Martin Heinrich Klaproth|url=https://books.google.com/books?id=YxQ_AAAAcAAJ&pg=PA387|journal=Chemische Annalen|volume=2|year=1789|pages=387–403}}</ref> Sixty years later, the French scientist [[Eugène-Melchior Péligot]] identified it as uranium oxide. He also isolated the first sample of uranium metal by heating [[uranium tetrachloride]] with metallic [[potassium]].<ref>{{cite journal| title=Recherches Sur L'Uranium|author=E.-M. Péligot|journal=[[Annales de chimie et de physique]]|volume=5|issue=5|year=1842|pages=5–47|url=http://gallica.bnf.fr/ark:/12148/bpt6k34746s/f4.table}}</ref> The [[atomic mass]] of uranium was then calculated as 120, but [[Dmitri Mendeleev]] in 1872 corrected it to 240 using his periodicity laws. This value was confirmed experimentally in 1882 by K. Zimmerman.<ref>{{cite book|doi=10.1007/1-4020-3598-5_5|author=Ingmar Grenthe|chapter=Uranium|title=The Chemistry of the Actinide and Transactinide Elements|pages=253–698|year=2006|isbn=978-1-4020-3555-5}}</ref><ref>K. Zimmerman, Ann., 213, 290 (1882); 216, 1 (1883); Ber. 15 (1882) 849</ref>

[[Thorium oxide]] was discovered by [[Friedrich Wöhler]] in the mineral [[thorianite]], which was found in Norway (1827).<ref>Golub, p. 214</ref> [[Jöns Jacob Berzelius]] characterized this material in more detail in 1828. By reduction of [[thorium tetrachloride]] with potassium, he isolated the metal and named it thorium after the [[norse mythology|Norse god]] of thunder and lightning [[Thor]].<ref>{{cite journal|author=Berzelius, J. J.|year=1829|url=http://gallica.bnf.fr/ark:/12148/bpt6k151010.pleinepage.r=Annalen+der+Physic.f395.langFR|title=Untersuchung eines neues Minerals und einer darin erhalten zuvor unbekannten Erde (Investigation of a new mineral and of a previously unknown earth contained therein)|journal=Annalen der Physik und Chemie|volume=16|pages=385–415|doi=10.1002/andp.18290920702|issue=7|bibcode=1829AnP....92..385B}} (modern citation: ''Annalen der Physik'', vol. 92, no. 7, pp. 385–415)</ref><ref>{{cite journal|author=Berzelius, J. J.|year=1829|title=Undersökning af ett nytt mineral (Thorit), som innehåller en förut obekant jord" (Investigation of a new mineral (thorite), as contained in a previously unknown earth)|journal=Kungliga Svenska Vetenskaps Akademiens Handlingar (Transactions of the Royal Swedish Science Academy)|url=http://ia800507.us.archive.org/30/items/kungligasvenska1182kung_2/kungligasvenska1182kung_2.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://ia800507.us.archive.org/30/items/kungligasvenska1182kung_2/kungligasvenska1182kung_2.pdf |archive-date=2022-10-09 |url-status=live|pages=1–30}}</ref> The same isolation method was later used by Péligot for uranium.<ref name=g1250 />

[[Actinium]] was discovered in 1899 by [[André-Louis Debierne]], an assistant of [[Marie Curie]], in the pitchblende waste left after removal of radium and polonium. He described the substance (in 1899) as similar to [[titanium]]<ref>{{cite journal|title=Sur un nouvelle matière radio-active|author=André-Louis Debierne|journal=Comptes Rendus|volume=129|pages=593–595|year=1899|url=http://gallica.bnf.fr/ark:/12148/bpt6k3085b/f593.table|language=fr}}</ref> and (in 1900) as similar to thorium.<ref>{{cite journal|title=Sur un nouvelle matière radio-actif – l'actinium|author=André-Louis Debierne|journal=Comptes Rendus|volume=130|pages=906–908|year=1900–1901|url=http://gallica.bnf.fr/ark:/12148/bpt6k3086n/f906.table|language=fr}}</ref> The discovery of actinium by Debierne was however questioned in 1971<ref>{{cite journal|title=The Discovery of Actinium|author=H. W. Kirby|journal=Isis|volume=62|issue=3|pages=290–308|year=1971|doi=10.1086/350760|jstor=229943|s2cid=144651011 }}</ref> and 2000,<ref>{{cite journal|title=The centenary of a controversial discovery: actinium|author=J. P. Adloff|journal=Radiochim. Acta|volume=88|pages=123–128|year=2000|doi=10.1524/ract.2000.88.3-4.123|issue=3–4_2000|s2cid=94016074 }}</ref> arguing that Debierne's publications in 1904 contradicted his earlier work of 1899–1900. This view instead credits the 1902 work of [[Friedrich Oskar Giesel]], who discovered a radioactive element named ''emanium'' that behaved similarly to lanthanum. The name actinium comes from the {{langx|grc|ακτίς, ακτίνος}} {{transliteration|grc|italic=no|(aktis, aktinos)}}, meaning beam or ray. This metal was discovered not by its own radiation but by the radiation of the daughter products.<ref>Golub, p. 213</ref><ref name="Himiya aktiniya">{{cite book|author1=Z. K. Karalova|author2=B. Myasoedov|title=Actinium|place=Moscow|publisher=[[Nauka (publisher)|Nauka]]|year=1982|series=Analytical chemistry items}}</ref> Owing to the close similarity of actinium and lanthanum and low abundance, pure actinium could only be produced in 1950. The term actinide was probably introduced by [[Victor Goldschmidt]] in 1937.<ref>{{cite journal|doi=10.1021/ed029p581.2|title=Letters|year=1952|last1=Hakala|first1=Reino W.|journal=Journal of Chemical Education|volume=29|issue=11|page=581|bibcode=1952JChEd..29..581H|doi-access=free}}</ref><ref>{{cite journal|doi=10.1007/s00897970143a|title=Victor Moritz Goldschmidt (1888–1947): A Tribute to the Founder of Modern Geochemistry on the Fiftieth Anniversary of His Death|year=1997|author=George B. Kauffman|author-link= George B. Kauffman|journal=The Chemical Educator|volume=2|issue=5|pages=1–26|s2cid=101664962 }}</ref><!-- He called them thorides in 1937-->

[[Protactinium]] was possibly isolated in 1900 by [[William Crookes]].<ref>{{cite book|title=Nature's Building Blocks: An A-Z Guide to the Elements|author=John Emsley|publisher=Oxford University Press|location=Oxford, England|isbn=978-0-19-850340-8|chapter=Protactinium|pages= 347–349|chapter-url=https://books.google.com/books?id=Yhi5X7OwuGkC|year=2001|url=https://archive.org/details/naturesbuildingb0000emsl/page/347}}</ref> It was first identified in 1913, when [[Kasimir Fajans]] and [[Oswald Helmuth Göhring]] encountered the short-lived isotope <sup>234m</sup>Pa (half-life 1.17 minutes) during their studies of the [[Decay chain#Uranium series|<sup>238</sup>U decay chain]]. They named the new element ''brevium'' (from Latin ''brevis'' meaning brief);<ref name=fajans>{{cite journal|author1=K. Fajans|author2=O. Gohring|title=Über die komplexe Natur des Ur X|journal=Naturwissenschaften|year=1913|volume=1|page=339|url=http://www.digizeitschriften.de/no_cache/home/jkdigitools/loader/?tx_jkDigiTools_pi1%5BIDDOC%5D=201162&tx_jkDigiTools_pi1%5Bpp%5D=425 |doi = 10.1007/BF01495360 |issue = 14|bibcode = 1913NW......1..339F |s2cid=40667401 }}</ref><ref>{{cite journal|author1=K. Fajans|author2=O. Gohring|title=Über das Uran X<sub>2</sub>-das neue Element der Uranreihe|journal=Physikalische Zeitschrift|year=1913|volume=14|pages=877–84}}</ref> the name was changed to ''protoactinium'' (from [[Greek language|Greek]] πρῶτος + ἀκτίς meaning "first beam element") in 1918 when two groups of scientists, led by the Austrian [[Lise Meitner]] and [[Otto Hahn]] of Germany and [[Frederick Soddy]] and [[John Arnold Cranston]] of Great Britain, independently discovered the much longer-lived <sup>231</sup>Pa. The name was shortened to ''protactinium'' in 1949. This element was little characterized until 1960, when [[Alfred Maddock]] and his co-workers in the U.K. isolated 130&nbsp;grams of protactinium from 60 tonnes of waste left after extraction of uranium from its ore.<ref name=g1251>Greenwood, p. 1251</ref>