francium


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fran·ci·um

 (frăn′sē-əm)
n. Symbol Fr
An extremely unstable radioactive element of the alkali metals, produced by alpha decay of actinium or artificially from thorium, having over 40 isotopes and isomers, the most stable of which is Fr-223 with a half-life of 22 minutes. Atomic number 87; melting point 27°C; boiling point 677°C; valence 1. See Periodic Table.

[After France.]

francium

(ˈfrænsɪəm)
n
(Elements & Compounds) an unstable radioactive element of the alkali-metal group, occurring in minute amounts in uranium ores. Symbol: Fr; atomic no: 87; half-life of most stable isotope, 223Fr: 22 minutes; valency: 1; melting pt: 27°C; boiling pt: 677°C
[C20: from New Latin, from France + -ium; so-called because first found in France]

fran•ci•um

(ˈfræn si əm)

n.
a radioactive element of the alkali metal group. Symbol: Fr; at. no.: 87.
[< French (1946), after France; see -ium2]

fran·ci·um

(frăn′sē-əm)
Symbol Fr An extremely unstable, radioactive element that is the heaviest alkali metal. Francium occurs in nature, but less than one ounce (30 grams) is present in the Earth's crust at any time. The most stable of its several isotopes has a half-life of 21 minutes. Atomic number 87. See Periodic Table.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.francium - a radioactive element of the alkali-metal group discovered as a disintegration product of actiniumfrancium - a radioactive element of the alkali-metal group discovered as a disintegration product of actinium
metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.
Translations

francium

[ˈfrænsɪəm] Nfrancio m
References in periodicals archive ?
While focusing on what might be called the first generation of women researchers (those born before 1900), the book also discusses in detail Marie Curie (1867-1934), who began her pioneering work in the 1890s and could be considered as belonging to the zeroth generation, and also mentions several representatives of the second generation such as Marguerite Perey (1909-1975), who discovered francium in 1939.
Of all the elements between 1 and 92, francium is the only one that possesses no isotope with a half-life of as much as half an hour.
At number 87 in the periodic table, francium is the least stable of the first 103 elements.