Chemistry

ACS is a congressionally chartered independent membership organization which represents professionals at all degree levels and in all fields of chemistry and sciences that involve chemistry.

From the ASDL, it "SDL, collects, catalogs, links and publishes peer reviewed web-based discovery materials pertinent to innovations in curricular development and supporting technical resources in the analytical sciences."

World repository of small molecule crystal structures.

A tool used to calculate the balanced equation and equilibrium constant when a chemical equation is given.

Provides free text and structure search access of millions of chemical structures across the web. It is the richest single source of structure-based chemistry information.

Provides information on nomenclature and symbols; there are links to websites about chemical elements; a few online publications are also available.

The Organic Chemistry Portal offers an overview of recent topics, interesting reactions, and information on important chemicals for organic chemists

Data on fundamental physical constants, atomic and molecular spectroscopy, ionization cross sections, absorption of x-rays and gamma rays, radiation dosimetry, half-life measurements, atomic weights, and condensed matter physics.

The UK’s professional body for chemical scientists that invest in educating future generations of scientists.

Periodic table on the web find key data on all of the elements.

From the ASDL, it "SDL, collects, catalogs, links and publishes peer reviewed web-based discovery materials pertinent to innovations in curricular development and supporting technical resources in the analytical sciences."