francium


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francium

 (Fr) [fran´se-um]
a chemical element, atomic number 87, atomic weight 223. (See Appendix 6.)

fran·ci·um (Fr),

(fran'sē-ŭm),
Radioactive element of the alkali metal series; atomic no. 87; half-life of most stable known isotope, 223Fr, is 21.8 min.
[France, native country of Marguerite Perey (1909-1975), the discoverer]

francium

/fran·ci·um/ (Fr) (fran´se-um) a chemical element, at. no. 87.

francium (Fr)

[fran′sē·əm]
Etymology: France
a metallic element of the alkali metal group. Its atomic number is 87, and the mass of its longest-lived isotope is 223. Formed from the decay of actinium, all of its 20 isotopes are radioactive and short-lived.

francium

A highly radioactive alkali metal (atomic number 87) that decays into astatine, radium and radon. Francium has no commercial utility due to its instability and rarity.

fran·ci·um

(Fr) (fran'sē-ŭm)
Radioactive element of the alkali metal series; atomic no. 87; half-life of most stable known isotope, 223Fr, is 21.8 minutes.
[France, native country of Marguerite Perey (1909-1975), the discoverer]

francium

a chemical element, atomic number 87, atomic weight 223, symbol Fr. See Table 6.
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References in periodicals archive ?
The researchers can now make extremely sensitive measurements of the light emitted and absorbed by the trapped atoms, providing the first experimental results on various transitions between atomic energy levels in francium.