A comprehensive resource of physical constants and properties.

Includeds thermodynamic, electrical, mechanical, and acoustical data. Run by the National Physical Laboratory, Middlesex, UK.

Naming convention information and guidance from the International Union of Pure and Applied Chemistry (IUPAC).

A source of property data on many organic compounds and a few common inorganic compounds. Maintained by the US Department of Commerce.

A free resource maintained by the Royal Society of Chemistry that contains property and spectra information.

A free search for chemical suppliers of over 9 million chemicals from 2,300 suppliers.

A quick look up for CAS Registry numbers for approximately 7,900 common chemicals of public interest.

Search for structures, substances, and bioassay records; part of PubMed

Includes electron impact mass, Fourier transform infrared, proton NMR, 13C NMR, laser Raman, and electron spin resonance spectra for approximately 34,000 compounds. Maintained by the National Institute of Advanced Industrial Science and Technology (AIST), Japan.

Many large research libraries maintain lists of specialized resources. University of Wisconsin-Madison Libraries is one example.

A database for finding commercial sources for various substances.

Chemical information database to find worldwide produces of lab and commercial chemicals for sale

Contains information about compounds sold by Millipore Sigma(formerly Sigma-Aldrich)