Actinium • Actinide Rare Earth
Symbol: Ac
Date of discovery: 1899
Name origin: Greek aktinos
Appearance: silvery
Discoverer: Andre Debierne
Obtained from: irradiation of Ra
Melting point: 1050 K
Boiling point: 3300 K
Density[kg/m3]: 10.07
Molar volume: 22.55 × 10-6 m3/mol
Protons/Electrons: 89
Neutrons: 138
Shell structure: 2,8,18,32,18,9,2
Electron configuration: [Rn]6d17s2
Oxidation state: 3
Crystal structure: cubic
Actinium is a silvery metallic element. Actinium gets its name from the Greek word aktinos, meaning beam or ray. Due to its intense radioactivity, actinium glows in the dark with a pale blue light. One hundred and fifty times as radioactive as radium, actinium presents severe health effects if ingested in even the slightest amount. Actinium is used to produce bismuth for medical applications or can be used on its own as an agent for radio-immunotherapy.
