CAS roles are powerful CAS indexing terms that allow you to search for precise information on substances. Roles are assigned to every indexed substance and to controlled index terms for classes of compounds. You can search specific roles and super roles; all are listed on the last page of this card.
The PREP (Preparation) role is assigned for documents from 1907 to the present. Most other CAS roles are available for documents from 1967 to date. You can search roles in all of the CA/CAplus family of databases.