See also:

• Science: Chemistry: Elements: Actinides  (2)

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	Portuguese  (1)

ChemGlobe: Actinium - Electronic, thermal, and steric data along with an isotope table..

ChemicalElements.com: Actinium - Basic information, atomic structure, and isotopes..

EnvironmentalChemistry.com: Actinium - Atomic structure, properties, and table of nuclides..

It's Elemental: Actinium - Basic physical and historical information..

LANL: Actinum - Basic information and history..

Lenntech: Actinium - Physical data, chemical properties, health and environmental effects..

Visual Elements: Actinium - Image, sources, biological role, key isotopes, and oxidation states..

WebElements: Actinium - Extensive information on history, uses, occurrence, compounds, and properties..

Wikipedia: Actinium - Details the properties of the element, including its history, applications, and characteristics..