Mercury

ChemGlobe: Mercury
Electronic, thermal, and steric data along with an isotope table.
http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/80.html

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

EnvironmentalChemistry.com: Mercury : Nuclides
Extensive information on the nuclides of mercury, including potential parent nuclides.
http://environmentalchemistry.com/yogi/periodic/Hg-pg2.html

It's Elemental: Mercury
Basic physical and historical information.
http://education.jlab.org/itselemental/ele080.html

LANL: Mercury
Basic information, history, and uses.
http://periodic.lanl.gov/elements/80.html

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

Mercury
A very brief description of Mercury, with a good diagram of its electron orbitals.
http://www.pleasantridge.k12.ca.us/magnolia/elements/mercury/mercury1.html

Mercury and Methylmercury by IC-ICPMS
Analysis of biological, pharmaceutical, and environmental samples for methylmercury and mercury.
http://www.wcas.com/tech/methylhg.htm

Mercury in Space
Answers the question of what happens to Mercury in space.
http://www.newton.dep.anl.gov/askasci/phy99/phy99189.htm

Mercury in the Laboratory
Practical considerations when working with mercury in the laboratory.
http://www.ilpi.com/safety/mercury.html

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

Vermont Legislative Research Shop - Mercury Information
Features basic information about Mercury, as well as its harmful effects and legislation concerning Mercury in some American States.
http://www.uvm.edu/~vlrs/doc/mercury.htm

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

WebElements: Mercury
Contains extensive information about Mercury, as well as pictures and videos that show its physical appearance and how it reacts with certain chemicals.
http://www.webelements.com/webelements/scholar/elements/mercury/key.html

Why is Mercury liquid at room temperature?
Explores the question of why Mercury is liquid at room temperature. It also provides some links to other sites regarding this chemistry quandary.
http://www.zyra.org.uk/mercliq.htm

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

Radiochemistry of Mercury
Full text of the monograph by Josef Roesmer (Westinghouse Astronuclear Laboratory, Pittsburgh, Pennsylvania). [PDF] <small>(September, 1970)</small>
http://library.lanl.gov/cgi-bin/getfile?rc000030.pdf