NO. 089Actinide

Ac

Actinium

Actinium is a soft, silvery radioactive metal and the first element of the actinide series. It is used mainly in scientific research and targeted cancer therapies.

Crystal Structure

Face-centered cubic

Technical Specifications

Atomic Mass227 u

Density10.1 g/cm³

Melting Point1323 K

Boiling Point3500 K

Atomic Radius195 pm

Electronegativity1.1

Ionization Energy499 kJ/mol

Electron Affinity35 kJ/mol

Bonding TypeMetallic

Oxidation States3

Acid/BaseBasic

ReactivityHigh

Electron Configuration

[Rn] 6d1 7s2

Discovered ByAndré-Louis Debierne

Year1899

Known Isotopes

Ac-227