Editing Francium (section)

==History==
As early as 1870, chemists thought that there should be an alkali metal beyond [[caesium]], with an atomic number of 87.<ref name="andyscouse" /> It was then referred to by the provisional name ''[[Mendeleev's predicted elements|eka-caesium]]''.<ref name="chemeducator">Adloff, Jean-Pierre; Kaufman, George B. (September 25, 2005). [http://chemeducator.org/sbibs/s0010005/spapers/1050387gk.htm Francium (Atomic Number 87), the Last Discovered Natural Element] {{Webarchive|url=https://web.archive.org/web/20130604212956/http://chemeducator.org/sbibs/s0010005/spapers/1050387gk.htm |date=June 4, 2013}} . ''The Chemical Educator'' '''10''' (5). Retrieved on March 26, 2007.</ref>

===Erroneous and incomplete discoveries===
In 1914, [[Stefan Meyer (physicist)|Stefan Meyer]], Viktor F. Hess, and [[Friedrich Paneth]] (working in Vienna) made measurements of alpha radiation from various substances, including <sup>227</sup>Ac. They observed the possibility of a minor alpha branch of this nuclide, though follow-up work could not be done due to the outbreak of [[World War I]]. Their observations were not precise and sure enough for them to announce the discovery of element 87, though it is likely that they did indeed observe the decay of <sup>227</sup>Ac to <sup>223</sup>Fr.<ref name=chemeducator/>

Soviet chemist [[Dmitry Dobroserdov]] was the first scientist to claim to have found eka-caesium, or francium. In 1925, he observed weak radioactivity in a sample of [[potassium]], another alkali metal, and incorrectly concluded that eka-caesium was contaminating the sample (the radioactivity from the sample was from the naturally occurring potassium radioisotope, [[potassium-40]]).<ref name="fontani">{{cite conference| first = Marco| last = Fontani |author-link= Marco Fontani | title = The Twilight of the Naturally-Occurring Elements: Moldavium (Ml), Sequanium (Sq) and Dor (Do)| book-title = International Conference on the History of Chemistry| pages = 1–8| date = September 10, 2005| location = Lisbon|url = http://5ichc-portugal.ulusofona.pt/uploads/PaperLong-MarcoFontani.doc| archive-url = https://web.archive.org/web/20060224090117/http://5ichc-portugal.ulusofona.pt/uploads/PaperLong-MarcoFontani.doc|archive-date=February 24, 2006|access-date = April 8, 2007}}</ref> He then published a thesis on his predictions of the properties of eka-caesium, in which he named the element ''russium'' after his home country.<ref name="vanderkroft">{{cite web| last = Van der Krogt| first = Peter| title = Francium| work = Elementymology & Elements Multidict| date = January 10, 2006| url = http://elements.vanderkrogt.net/element.php?sym=Fr| access-date = April 8, 2007}}</ref> Shortly thereafter, Dobroserdov began to focus on his teaching career at the Polytechnic Institute of [[Odesa]], and he did not pursue the element further.<ref name="fontani" />

The following year, English chemists [[Gerald J. F. Druce]] and [[Frederick H. Loring]] analyzed [[X-ray]] photographs of [[manganese(II) sulfate]].<ref name="vanderkroft" /> They observed spectral lines which they presumed to be of eka-caesium. They announced their discovery of element 87 and proposed the name ''alkalinium'', as it would be the heaviest alkali metal.<ref name="fontani" />

In 1930, [[Fred Allison]] of the [[Alabama Polytechnic Institute]] claimed to have discovered element 87 (in addition to 85) when analyzing [[pollucite]] and [[lepidolite]] using his [[magneto-optic effect|magneto-optical]] machine. Allison requested that it be named ''virginium'' after his home state of [[Virginia]], along with the symbols Vi and Vm<!--along with them how? and proposed the symbols Vi and Vm?-->.<ref name="vanderkroft" /><ref>{{cite magazine| title = Alabamine & Virginium| magazine = [[Time (magazine)|Time]] | date = February 15, 1932|url = http://www.time.com/time/magazine/article/0,9171,743159,00.html|archive-url = https://web.archive.org/web/20070930015028/http://www.time.com/time/magazine/article/0,9171,743159,00.html|url-status = dead|archive-date = September 30, 2007| access-date = April 1, 2007}}</ref> In 1934, H.G. MacPherson of [[University of California, Berkeley|UC Berkeley]] disproved the effectiveness of Allison's device and the validity of his discovery.<ref>{{cite journal| last = MacPherson| first = H. G.| title = An Investigation of the Magneto-Optic Method of Chemical Analysis| journal = Physical Review| volume = 47| issue = 4| pages = 310–315|date=1934|doi = 10.1103/PhysRev.47.310|bibcode = 1935PhRv...47..310M}}</ref>

In 1936, Romanian physicist [[Horia Hulubei]] and his French colleague [[Yvette Cauchois]] also analyzed pollucite, this time using their high-resolution X-ray apparatus.<ref name="fontani" /> They observed several weak emission lines, which they presumed to be those of element 87. Hulubei and Cauchois reported their discovery and proposed the name ''moldavium'', along with the symbol Ml, after [[Moldavia]], the Romanian province where Hulubei was born.<ref name="vanderkroft" /> In 1937, Hulubei's work was criticized by American physicist [[F. H. Hirsh Jr.]], who rejected Hulubei's research methods. Hirsh was certain that eka-caesium would not be found in nature, and that Hulubei had instead observed [[mercury (element)|mercury]] or [[bismuth]] X-ray lines. Hulubei insisted that his X-ray apparatus and methods were too accurate to make such a mistake. Because of this, [[Jean Baptiste Perrin]], [[Nobel Prize]] winner and Hulubei's mentor, endorsed moldavium as the true eka-caesium over [[Marguerite Perey]]'s recently discovered francium. Perey took pains to be accurate and detailed in her criticism of Hulubei's work, and finally she was credited as the sole discoverer of element 87.<ref name="fontani" /> All other previous purported discoveries of element 87 were ruled out due to francium's very limited half-life.<ref name="vanderkroft" />

===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>