Symbol Ac
Atomic Number 89
Atomic Mass 227 g.mol -1
Discovered by Andre Debierne in 1899

Chemical Properties of Actinium

Group Actinides Melting point 1050°C, 1922°F, 1323 K
Period 7 Boiling point 3200°C, 5792°F, 3473 K
Block d Density (g cm−3) Unknown
Atomic number 89 Relative atomic mass [227]  
State at 20°C Solid Key isotopes 227Ac 
Electron configuration [Rn]  6d17s2  CAS number 7440-34-8
ChemSpider ID 22404 ChemSpider is a free chemical structure database

What is Actinium?

  • Actinium is a radioactive element with an atomic number 89 of the periodic table
  • It has the physical appearance of metallic silver.
  • In nature, it is found in traces of most of the Uranium ores.
  • Due to intense radioactivity, this metal glows blue in the dark.
  • It also shares similar properties to that of lanthanum.

Uses of Actinium

  • Actinium does not find much significant use in any industrial application.
  • It is a vital source of alpha rays.
  • Actinium-225 is used in the field of medicine as an agent for radiation therapy.
  • It has immense value as a neutron source as it is one fifty times more radioactive than compared to radium.

Properties of Actinium

  • This radioactive element reacts with oxygen to form a white coating like substance called actinium oxide. Thus preventing the metal from further getting oxidized.
  • The actinium ions appear colorless when kept in a solution. It is one among the strongest of radioactive elements.

Practise This Question

The oxidation number of N in N2H+5