http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Names, synonyms, and structures of organic compounds
v. 1. CAS number 50-00-0 to 2433-97-8 -- v. 2. CAS number 2435-53-2 to 127665-32-1 -- v. 3. Molecular formula index, name/synonym index.