NO. 087Alkali

Fr

Francium

Francium is an extremely rare and highly radioactive Alkali. It is the most unstable of the naturally occurring elements and has no commercial applications.

Crystal Structure

Body-centered cubic

Technical Specifications

Atomic Mass223 u

Density1.87 g/cm³

Melting Point300 K

Boiling Point950 K

Atomic Radius260 pm

Electronegativity0.7

Ionization Energy380 kJ/mol

Electron Affinity47 kJ/mol

Bonding TypeMetallic

Oxidation States1

Acid/BaseBasic

ReactivityHigh

Electron Configuration

[Rn] 7s1

Discovered ByMarguerite Perey

Year1939

Known Isotopes

Fr-223