Editing Francium (section)

===Perey's analysis===
Eka-caesium was discovered on January 7, 1939, by [[Marguerite Perey]] of the [[Curie Institute (Paris)|Curie Institute]] in Paris,<ref name=chemeducator/> when she purified a sample of [[actinium]]-227 which had been reported to have a decay energy of 220&nbsp;keV. Perey noticed decay particles with an energy level below 80&nbsp;keV. Perey thought this decay activity might have been caused by a previously unidentified decay product, one which was separated during purification, but emerged again out of the pure actinium-227. Various tests eliminated the possibility of the unknown element being [[thorium]], radium, [[lead]], bismuth, or [[thallium]]. The new product exhibited chemical properties of an alkali metal (such as coprecipitating with caesium salts), which led Perey to believe that it was element 87, produced by the [[alpha decay]] of actinium-227.<ref name="chemeducator" /> Perey then attempted to determine the proportion of [[beta decay]] to alpha decay in actinium-227. Her first test put the alpha branching at 0.6%, a figure which she later revised to 1%.<ref name="mcgraw" />

Perey named the new isotope ''actinium-K'' (it is now referred to as francium-223)<ref name="chemeducator" /> and in 1946, she proposed the name ''catium'' (Cm) for her newly discovered element, as she believed it to be the most [[electronegativity|electropositive]] [[cation]] of the elements. [[Irène Joliot-Curie]], one of Perey's supervisors, opposed the name due to its connotation of ''cat'' rather than ''cation''; furthermore, the symbol coincided with that which had since been assigned to [[curium]].<ref name="chemeducator" /> Perey then suggested ''francium'', after France. This name was officially adopted by the [[International Union of Pure and Applied Chemistry]] (IUPAC) in 1949,<ref name="andyscouse" /> becoming the second element after [[gallium]] to be named after France. It was assigned the symbol Fa, but it was revised to the current Fr shortly thereafter.<ref name="hackh">{{Cite book| last = Grant| first = Julius| contribution = Francium| date = 1969| title = Hackh's Chemical Dictionary| pages = 279–280| publisher = McGraw-Hill| isbn = 978-0-07-024067-4}}</ref> Francium was the last element discovered in nature, rather than synthesized, following [[hafnium]] and [[rhenium]].<ref name="chemeducator" /> Further research into francium's structure was carried out by, among others, [[Sylvain Lieberman]] and his team at [[CERN]] in the 1970s and 1980s.<ref>{{cite web
 |title       = History
 |work        = Francium
 |publisher   = [[State University of New York at Stony Brook]]
 |date        = February 20, 2007
 |url         = http://fr.physics.sunysb.edu/francium_news/history.HTM
 |access-date = March 26, 2007
 |url-status  = dead
 |archive-url = https://archive.today/19990203121919/http://fr.physics.sunysb.edu/francium_news/history.HTM
 |archive-date = February 3, 1999
 |df          = mdy-all
}}</ref>