Actinium (Ac)
"The Blue Glow, a hero who is so radioactive it makes the very air around it glow."
A memorable persona to anchor Ac in your mind.
10.07
Grams per cm³
1050
Celsius (°C)
260
Radius (pm)
Daily Life Link
Actinium has no everyday connection, used only in research.
Discovery & History
Year Discovered
1899
Discovered By
André-Louis Debierne
Origin of Name
"The name is derived from the Greek ''actinos'', meaning a ray."
Technical Properties
Atomic Mass
[227] u
Standard State
solid
Boiling Point
3200°C
Electron Configuration
[Rn] 6d17s2
1st Ionization Energy
5.17 eV
Electron Affinity
N/A
Oxidation States
"Actinium is a silvery, highly radioactive metal that glows blue in the dark."
Did You Know?
Its name comes from the Greek word 'aktis' or 'aktinos', meaning 'beam' or 'ray', due to its intense radioactivity.
It glows in the dark with an eerie pale blue light. This is not due to phosphorescence, but because its intense radioactivity excites the nitrogen and oxygen atoms in the surrounding air, causing them to emit light.
It is about 150 times more radioactive than radium.
It is the first element in the actinide series, which is named after it.