CAS REGISTRY®, the CAS substance collection, is the premier source relied upon by scientists and regulators worldwide for accurate information on chemical substances.

CAS Registry Numbers (CAS RN) are simple and regular, convenient for database searches. They offer a reliable, common and international link to every specific substance across the various …

Chemsrc provides fast access to over millions CAS#/CAS Number Database, including structure, MSDS, melting point, boiling point, density, etc.

“CAS registry” is a registered trademark of the American Chemical society.

Each number represents only one substance and has no chemical significance but serves solely as an internationally observed substance identifier by scientists, industry and regulatory organizations.

Sep 15, 2025 · You can also identify your substance of interest by its CAS Registry Number®, which is universally used to provide a unique, unmistakable identifier for chemical substances.

Quickly confirm chemical names, CAS Registry Numbers®, structures or basic physical properties by searching compounds of general interest or leveraging an API connection.