Britannica Nobel Prize: Technetium
   Overview and basic data.
   http://www.britannica.com/nobel/micro/584_98.html

ChemGlobe: Technetium
   Electronic, thermal, and steric data along with an isotope table.
   http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/43.html

ChemicalElements.com: Technetium
   Basic information, atomic structure, and isotopes.
   http://www.chemicalelements.com/elements/tc.html

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

It's Elemental: Technetium
   Basic physical and historical information.
   http://education.jlab.org/itselemental/ele043.html

LANL: Technetium
   History, isotopes, properties, and handling.
   http://periodic.lanl.gov/elements/43.html

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

Radiochemistry of Technetium
   Full text of the monograph by Edward Anders (Enrico Fermi Institute and Dept. of Chemistry, University of Chicago, Chicago, Illinois). [PDF format]
   http://lib-www.lanl.gov/cgi-bin/getfile?rc000035.pdf

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

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