Thallium
Links
Visual Elements: Thallium
http://www.chemsoc.org/viselements/pages/thallium.html
Image, source, uses, physical information, and key isotopes.
It's Elemental: Thallium
http://education.jlab.org/itselemental/ele081.html
Basic physical and historical information.
ChemicalElements.com: Thallium
http://www.chemicalelements.com/elements/tl.html
Basic information, atomic structure, and isotopes.
USGS Minerals Information: Thallium
http://minerals.usgs.gov/minerals/pubs/commodity/thallium/
Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
Thallium
http://www.scescape.net/~woods/elements/thallium.html
Data tables and historic information.
EnvironmentalChemistry.com: Thallium
http://environmentalchemistry.com/yogi/periodic/Tl.html
Atomic structure, chemical and physical properties, and table of nuclides.
WebElements: Thallium
http://www.webelements.com/webelements/elements/text/Tl/key.html
Extensive information on history, uses, occurrence, compounds, and properties.
Wikipedia: Thallium
http://www.wikipedia.org/wiki/Thallium
Properties of the element, including its history, applications, and charateristics.
Lenntech: Thallium
http://www.lenntech.com/Periodic-chart-elements/Tl-en.htm
Physical data, chemical properties, health and environmental effects.