Editing Actinium (section)

==History==
[[André-Louis Debierne]], a French chemist, announced the discovery of a new element in 1899. He separated it from [[uraninite|pitchblende]] residues left by [[Marie Curie|Marie]] and [[Pierre Curie]] after they had extracted [[radium]].<ref name="Adloff"/> In 1899, Debierne described the substance as similar to [[titanium]]<ref>{{cite journal |title = Sur un nouvelle matière radio-active |first = André-Louis |last = Debierne |journal = Comptes Rendus |volume = 129 |pages = 593–595 |date = 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 |first = André-Louis |last = Debierne |journal = Comptes Rendus |volume = 130 |pages = 906–908 |date = 1900–1901 |url=http://gallica.bnf.fr/ark:/12148/bpt6k3086n/f906.table |language=fr}}</ref> [[Friedrich Oskar Giesel]] found in 1902<ref>{{cite journal |title = Ueber Radium und radioactive Stoffe |first = Friedrich Oskar |last = Giesel |journal = Berichte der Deutschen Chemischen Gesellschaft |volume = 35 |issue = 3 |pages = 3608–3611 |date = 1902 |doi = 10.1002/cber.190203503187 |language=de|url=https://zenodo.org/record/1426058 }}</ref> a substance similar to [[lanthanum]] and called it "emanium" in 1904.<ref>{{cite journal |title = Ueber den Emanationskörper (Emanium) |first = Friedrich Oskar |last = Giesel |journal = Berichte der Deutschen Chemischen Gesellschaft |volume = 37 |issue = 2 |pages = 1696–1699 |date = 1904 |doi = 10.1002/cber.19040370280 |language=de|url=https://zenodo.org/record/1426108 }}</ref> After a comparison of the substances' half-lives determined by Debierne,<ref>{{cite journal |title = Sur l'actinium |first = André-Louis |last = Debierne |journal = Comptes Rendus |volume = 139 |pages = 538–540 |date = 1904 |language=fr}}</ref> [[Harriet Brooks]] in 1904, and [[Otto Hahn]] and [[Otto Sackur]] in 1905, Debierne's chosen name for the new element was retained because it had seniority, despite the contradicting chemical properties he claimed for the element at different times.<ref>{{cite journal |title = Ueber Emanium |first = Friedrich Oskar |last = Giesel |journal = Berichte der Deutschen Chemischen Gesellschaft |volume = 37 |issue = 2 |pages = 1696–1699 |date = 1904 |doi = 10.1002/cber.19040370280 |language=de|url=https://zenodo.org/record/1426108 }}</ref><ref>{{cite journal |title = Ueber Emanium |first = Friedrich Oskar |last = Giesel |journal = Berichte der Deutschen Chemischen Gesellschaft |volume = 38 |issue = 1 |pages = 775–778 |date = 1905 |doi = 10.1002/cber.190503801130 |url=https://zenodo.org/record/1426124 |language=de}}</ref>

Articles published in the 1970s<ref name="discovery">{{cite journal |title = The Discovery of Actinium |first = Harold W. |last = Kirby |journal = Isis |volume = 62 |issue = 3 |pages = 290–308
|date = 1971 |jstor=229943 |doi =10.1086/350760|s2cid = 144651011 }}</ref> and later<ref name="Adloff">{{cite journal |title = The centenary of a controversial discovery: actinium |first = J. P. |last = Adloff |journal = Radiochim. Acta |volume = 88 |pages = 123–128 |date = 2000 |doi = 10.1524/ract.2000.88.3-4.123 |issue = 3–4_2000|s2cid = 94016074 }}</ref> suggest that Debierne's results published in 1904 conflict with those reported in 1899 and 1900. Furthermore, the now-known chemistry of actinium precludes its presence as anything other than a minor constituent of Debierne's 1899 and 1900 results; in fact, the chemical properties he reported make it likely that he had, instead, accidentally identified [[protactinium]], which would not be discovered for another fourteen years, only to have it disappear due to its hydrolysis and adsorption onto his [[laboratory equipment]]. This has led some authors to advocate that Giesel alone should be credited with the discovery.<ref name="Kirby" /> A less confrontational vision of scientific discovery is proposed by Adloff.<ref name="Adloff" /> He suggests that hindsight criticism of the early publications should be mitigated by the then nascent state of radiochemistry: highlighting the prudence of Debierne's claims in the original papers, he notes that nobody can contend that Debierne's substance did not contain actinium.<ref name="Adloff" /> Debierne, who is now considered by the vast majority of historians as the discoverer, lost interest in the element and left the topic. Giesel, on the other hand, can rightfully be credited with the first preparation of radiochemically pure actinium and with the identification of its atomic number 89.<ref name="discovery" />

The name actinium originates from the [[Ancient Greek]] ''aktis, aktinos'' (ακτίς, ακτίνος), meaning beam or ray.<ref name="CRC" /> Its symbol Ac is also used in abbreviations of other compounds that have nothing to do with actinium, such as [[acetyl]], [[acetate]]<ref>{{cite book |author1=Gilley, Cynthia Brooke |author2=University of California, San Diego. Chemistry |title=New convertible isocyanides for the Ugi reaction; application to the stereoselective synthesis of omuralide |url=https://books.google.com/books?id=vJQPInUTy3QC&pg=PR11 |date=2008 |isbn=978-0-549-79554-4 |page=11}}</ref> and sometimes [[acetaldehyde]].<ref>{{cite book |author=Reimers, Jeffrey R. |title=Computational Methods for Large Systems: Electronic Structure Approaches for Biotechnology and Nanotechnology |url=https://books.google.com/books?id=Ca9z4_cH-W8C&pg=PA575 |date= 2011 |publisher=John Wiley and Sons |isbn=978-0-470-48788-4 |page=575}}</ref>