Iridium

ChemGlobe: Iridium - Electronic, thermal, and steric data along with an isotope table.
http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/77.html

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

Visual Elements: Iridium - Image, general and physical information, source, uses, key isotopes, and ionisation energies.
http://www.chemsoc.org/viselements/pages/iridium.html

It's Elemental: Iridium - Basic physical and historical information.
http://education.jlab.org/itselemental/ele077.html

LANL: Iridium - History, properties, uses, and sources.
http://periodic.lanl.gov/elements/77.html

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

Radiochemistry of Iridium - Full text of the monograph by G. W. Leddicotte (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF] <small>(October, 1961)</small>
http://library.lanl.gov/cgi-bin/getfile?rc000027.pdf

ChemicalElements.com: Iridium - Basic information, atomic structure, and table of isotopes.
http://www.chemicalelements.com/elements/ir.html

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

WebElements: Iridium - Extensive information on history, uses, occurrence, compounds, and properties.
http://www.webelements.com/iridium/