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.]

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

francium

(ˈfrænsɪəm)

(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]

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

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.

The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

ThesaurusAntonymsRelated WordsSynonymsLegend:

Noun

francium - a radioactive element of the alkali-metal group discovered as a disintegration product of actinium

atomic number 87, Fr

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

francio

francium

[ˈfrænsɪəm] N → francio m

Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005

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References in periodicals archive

They were to select (a) a periodic, which included lithium, hydrogen, cesium, francium, sodium, rubidium, and potassium; (b) an isotope, which included kalium, oxygen, deuterium, and tritium; (c) an imaginary number, which included Jerion, Mark's Horse, or Bromius; (d) Mark Carscian, an adult human male and an official representative of the Mathematician; and (e) the Mathematician, who is the ruler of the Land of Mathematics and was described as a tiny, kind-hearted, white-bearded man who wore a simple crown.

Using Literature in Mathematics: Gifted Student's Comments

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.

A Devotion to Their Science: Pioneer Women of Radioactivity

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.

Francium