ChemGlobe: Astatine
- Electronic, thermal, and steric data, along with a table of isotopes.
- http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/85.html

LANL: Astatine
- History, uses, production, and properties.
- http://periodic.lanl.gov/elements/85.html

Wikipedia: Astatine
- Properties of the element, including its history, applications, and characteristics.
- http://en.wikipedia.org/wiki/Astatine

Lenntech: Astatine
- Physical data, chemical properties, and health effects.
- http://www.lenntech.com/Periodic-chart-elements/At-en.htm

EnvironmentalChemistry.com: Astatine
- Atomic structure, chemical and physical properties, and table of nuclides.
- http://environmentalchemistry.com/yogi/periodic/At.html

Visual Elements: Astatine
- General and physical information, source, key isotopes, and ionisation energies.
- http://www.chemsoc.org/viselements/pages/astatine.html

Chemical Elements.com: Astatine
- Basic information, atomic structure, and table of isotopes.
- http://www.chemicalelements.com/elements/at.html

It's Elemental: Astatine
- Basic physical and historical information.
- http://education.jlab.org/itselemental/ele085.html

Radiochemistry of Astatine
- Full text of the monograph by Evan H. Appelman (Argonne National Laboratory, Lemont, Illinois). [PDF]
- http://lib-www.lanl.gov/cgi-bin/getfile?rc000018.pdf

Britannica Nobel Prize: Astatine
- Overview and basic data.
- http://www.britannica.com/nobel/micro/38_12.html