Cadmium

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

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

ChemicalElements.com: Cadmium - Basic information, atomic structure, and isotopes.
http://www.chemicalelements.com/elements/cd.html

LANL: Cadmium - Basic information, history, uses, and cost.
http://periodic.lanl.gov/elements/48.html

USGS Minerals Information: Cadmium - Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
http://minerals.usgs.gov/minerals/pubs/commodity/cadmium/

It's Elemental: Cadmium - Basic physical and historical information.
http://education.jlab.org/itselemental/ele048.html

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

ChemGlobe: Cadmium - Electronic, thermal, and steric data along with an isotope table.
http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/48.html

WebElements: Cadmium - Extensive information on history, uses, occurrence, compounds, and properties.
http://www.webelements.com/webelements/elements/text/Cd/key.html

Visual Elements: Cadmium - Image, uses, physical information, key isotopes, and ionisation energies.
http://www.chemsoc.org/viselements/pages/cadmium.html