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.

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

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

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 · 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 …

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

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, …

What is CAS and what do we do? CAS is a division of the American Chemical Society (ACS) and is dedicated to the ACS vision of improving people's lives through the transforming power of …