Structure searching in CAS Online using STN Express:
An introductory workshop

CAS Registry File: Substance-based information

The Registry file contains records for chemical substances from 1957 to the present. More than 17 million substance records are in the Registry file. More than one million new substance records were added to the Registry File in 1996. The file is updated weekly.

All types of chemical substances are indexed in the file:

  • biochemical compounds including protein and nucleic acid sequences
  • inorganic compounds
  • metals and alloys
  • organic compounds
  • organometallic compounds
  • natural product compounds
  • polymers
  • commercially shipped chemical products

Substance records in the file contain:

  • chemical names and synonyms
  • molecular formula
  • structures
  • sequences
  • CAS Registry Numbers

Each is an access point to additional information about the chemical substance.