Element Francium

Francium ElementElement Francium atom is an alkali metal atom.
A radioactive alkali metal with the atomic symbol Fr, and atomic number 87. The mass numbers of known isotopes are 204-213, 217-224. Its valence is +1.
Prior to its discovery, it was referred to as eka-caesium. It is extremely radioactive; its most stable isotope, francium-223 (originally called actinium K after the natural decay chain it appears in), has a half-life of only 22 minutes.
Bulk francium has never been viewed. Because of the general appearance of the other elements in its periodic table column, it is assumed that francium would appear as a highly reactive metal, if enough could be collected together to be viewed as a bulk solid or liquid. Obtaining such a sample is highly improbable, since the extreme heat of decay caused by its short half-life would immediately vaporize any viewable quantity of the element.

Names and Identifiers

Chemical Formula:Fr
Molecular Weight:223.00000 g/mol
EC Number :n/a
MDL Number:n/a
Other Names:n/a
PubChem CID:6328145
IUPAC Name:Francium
Canonical SMILES:[Fr]
ICSC Number:n/a

Physical & Chemical Properties

Density:2.48 g/cm³
Boiling Point:890 K ​(620 °C, ​1150 °F)
Melting Point:281.0 K ​(8.0 °C, ​46.4 °F)
Molecular Formula:Fr
Flash Point:n/a
Exact Mass:223.02000

There are 34 known isotopes of francium ranging in atomic mass from 199 to 232.
Francium has seven metastable nuclear isomers.
Francium-223 and francium-221 are the only isotopes that occur in nature, though the former is far more common.

Radiosotope data

IsotopeMass/DaHalf-lifeMode of decayNuclear spinNuclear magnetic moment
210Fr209.996403.2 mα to 206At; EC to 210Rn64.4
211Fr210.995533.10 mα to 207At; EC to 211Rn9/24.0
212Fr211.9961820 mα to 208At; EC to 212Rn54.6
213Fr212.9961734.6 sα to 209At; EC to 213Rn9/24.0
214Fr213.998950.0051 sα to 210At1
215Fr215.000330.0000012 sα to 211At9/2
216Fr216.003190.000007 sα to 212At; EC to 216Rn
217Fr217.004620.00016 sα to 213At
218Fr218.007560.001 sα to 214At1
219Fr219.009240.021 sα to 215At9/2
220Fr220.0123127.4 sα to 216At; β to 220Ra1
221Fr221.014254.8 mα to 217At; β to 221Ra; 14C5/21.58
222Fr222.0175414.3 mβ to 222Ra20.63
223Fr223.019733 (4)22 mα to 219At; β to 223Ra3/21.17
224Fr224.023233 mβ to 224Ra10.40
225Fr225.025613.9 mβ to 225Ra3/21.07
226Fr226.029349 sβ to 226Ra10.071
227Fr227.03182.48 mβ to 227Ra1/21.50

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