WebElements: Actinium WebElements: Actinium: Extensive information on history, uses, occurrence, compounds, and properties. (Actinium) http://www.webelements.com/webelements/elements/text/Ac/key.html
ChemGlobe: Actinium ChemGlobe: Actinium: Electronic, thermal, and steric data along with an isotope table. (Actinium) http://www.vcs.ethz.ch/chemglobe/ptoe/_/89.html
Wikipedia: Actinium Wikipedia: Actinium: Details the properties of the element, including its history, applications, and charateristics. (Actinium) http://www.wikipedia.org/wiki/Actinium
Visual Elements: Actinium Visual Elements: Actinium: Image, sources, biological role, key isotopes, and oxidation states. (Actinium) http://www.chemsoc.org/viselements/pages/actinium.html
Actinium Actinium: Data tables and historic information. (Actinium) http://www.scescape.net/~woods/elements/actinium.html
EnvironmentalChemistry.com: Actinium EnvironmentalChemistry.com: Actinium: Atomic structure, properties, and table of nuclides. (Actinium) http://environmentalchemistry.com/yogi/periodic/Ac.html
Lenntech: Actinium Lenntech: Actinium: Physical data, chemical properties, health and environmental effects. (Actinium) http://www.lenntech.com/Periodic-chart-elements/Ac-en.htm
LANL: Actinum LANL: Actinum: Basic information and history. (Actinium) http://pearl1.lanl.gov/periodic/elements/89.html