Services and products of the American Chemical Society, the world's largest scientific society.
The University of Liverpool and its department of chemistry designed and manage this site. It indexes more than 7,500 chemistry Web resources in more than 60 categories.
NIST Chemistry WebBook - http://webbook.nist.gov/chemistry/
An authoritative database (by the former National Bureau of Standards) representing critical evaluation of relevant data by experts. Broad coverage including thermochemistry for 5,000 compounds, ion energetics for 14,000 compounds, and more.
Periodic Table of the Elements (www.periodictable.com)
Offers quick and easy factual information about the elements. Also includes images.
Energy, Science, & Technology Information Resources - U.S. Department of Energy (DOE).
Includes info on chemistry organizations, academic programs, and resources, plus lots more.