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

A CAS Registry Number[1] (also referred to as CAS RN[2] or informally CAS Number) is a unique identification number, assigned by the Chemical Abstracts Service (CAS) in the US to every …

CAS registry numbers are copyrighted by the American Chemical Society. Redistribution rights for CAS registry numbers are reserved by the American Chemical Society.

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

Dec 16, 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.

CAS (Chemical Abstracts Service) is a division of the American Chemical Society. It is a source of chemical information and is located in Columbus, Ohio, United States.

Oct 8, 2024 · A CAS number is a unique identifier assigned to every chemical substance described in the open scientific literature. This number, typically comprising up to ten digits, …

Chemical Abstracts Service (CAS), a division of the American Chemical Society, assigns these identifiers to every chemical that has been described in the literature.

CAS provides solutions and services that help empower scientific discoveries. Learn how CAS can facilitate your research and drive innovation.

Dec 22, 2025 · The CAS Content Collection now includes life sciences data curated by our expert scientists. Answer key drug discovery questions with structure-activity relationships, …