Chemistry

An interactive periodical table of the elements.

Website of the American Chemical Society.

The site includes selected classic papers relating to the history of chemistry, classic calculations, and the development of the concepts of elements and atoms, as well as featuring a history of chemistry calendar.

The Khan Academy offers free, self-paced educational courses on a variety of topics, including high school through college-level Chemistry.

The Cambridge Crystallographic Data Centre is a leading provider of structural databases and software for pharmaceutical discovery, materials development, research and education. The CCDC compiles and distributes the Cambridge Structural Database (CSD), the world's repository of experimentally determined organic and metal-organic crystal structures, and related applications software.

A guide to disclosed scientific and technical research (including existing patents) produced by the Chemical Abstracts Service (CAS), a division of the American Chemical Society.

This resource converts just about any unit of measure to any other. The site handles over 5,000 units, and 50,000 conversions.