A site devoted to Material Safety Data Sheets with links to over 100 free sites on the Internet.
Still more on material safety data sheets.
This free database is owned by the Royal Society of Chemistry and provides information on structures, properties, and other information.
Arranged alphabetically by state, here are links to the web pages of chemistry and biochemistry departments at four-year academic institutions in the United States which offer a bachelor's degree or higher in chemistry or biochemistry. Departmental pages will generally provide information about faculty, degrees offered, curriculum, courses offered and general contact information.
With a membership of over 151,000, the American Chemical Society is the world’s largest scientific society and a major influence in the world chemical literature. Their ChemCenter web site is a multilayered site with lots of information available - some pages are available to all, some only to subscribers, and some only to members. They provide excellent resources and extensive links to other useful sites.
From the Centre for Research in Computational Chemistry in Montreal, F*A*C*T's highlights include its free, easily searchable databases: Compound-Web, Reaction-Web, Equilib-Web, and Aqualib-Web. With Compound-Web, for example, users enter up to four elements or one compound and the program gives compounds of the elements or phases of the compound. All four databases have instructions.
The site provides access to several Fisher Scientific Catalogs including the Fisher Chemical Catalog and the ACROS Organics Catalog. The Fisher Chemical and ACROS catalogs also link to Material Safety Data Sheets.
There are numerous versions of the Periodic Table of the Elements available on the World Wide Web.
Periodic Table of the Elements -- from Los Alamos National Laboratory
WebElements -- from University of Sheffield, England