Actinium

89
Ac
227.0278








Used as a neutron source

Properties

Symbol Name Atomic Number Atomic Weight Group Number
Ac Actinium 89 227.0278

Description

Standard State: solid at 298 K
Color: silvery

Actinium was discovered by Andre Debierne in 1899 and independently by F. Giesel in 1902. Actinium is a very powerful source of alpha rays and is dangerously radioactive. It is found naturally in uranium ores and actinium is 150 times more radioactive than radium.