ChemGlobe: Tin
   Electronic, thermal, and steric data along with an isotope table.
   http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/50.html

ChemicalElements.com: Tin
   Basic information, atomic structure, and isotopes table.
   http://www.chemicalelements.com/elements/sn.html

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

It's Elemental: Tin
   Basic physical and historical information.
   http://education.jlab.org/itselemental/ele050.html

LANL: Tin
   Sources, properties, forms, and handling.
   http://periodic.lanl.gov/elements/50.html

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

Radiochemistry of Tin
   Full text of the monograph by W. E. Nervik (Lawrence Radiation Laboratory, University of California, Livermore, California). [PDF]
   http://lib-www.lanl.gov/cgi-bin/getfile?rc000007.pdf

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

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

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