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.

CAS numbers are unique numbers assigned to chemical substances by the Chemical Abstract Service to provide a consistent and reliable way of identifying the chemical substances.

Dec 22, 2025 · CAS builds the world’s largest collection of human-curated scientific knowledge covering over 150 years of published science. Our tools are designed to address the …

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.

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, …

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

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