The ChEBI database is an online dictionary of distinct entities focused on small chemical compounds encompassing molecule, ions, ion pairs, radicals, radical ions, complexes, conformers, etc. which are either natural products or synthetic products used to intervene in the processes of living organisms. The nomenclature, symbolism and terminology used are endorsed by international scientific bodies including the International Union of Pure and Applied Chemistry (IUPAC)

The data provided include:

• Structure - graphical representation(s) of a molecular structure and associated molfile(s)
• IUPAC International Chemical Identifier (InChI) and SMILES strings
• Molecular formula
• IUPAC name
• Synonyms
• Registry numbers - CAS Registry Number, Beilstein Registry Number, Gmelin Registry Number  (if available)      

Check out the free of charge chemical information link for other useful resources