1.Chemexper.com
ChemExper is a company joining together the areas of chemistry, computer science and telecommunication. The ChemExper Chemical Directory is a free service that allows to find a chemical by its molecular formula, IUPAC name, common name, CAS number, catalog number, substructure or physical characteristics as well as chemical suppliers. This database contains currently more than 10 millions chemicals, 16000 MSDS, 10000 IR spectra and more than 2000 chemical suppliers. You may also SUBMIT your own data!