CAS (Chemical Abstracts Service)

Chemical Abstracts Service (CAS) is a division of the American Chemical Society (ACS) that provides the world’s most comprehensive and authoritative collection of chemical information. Founded in 1907, CAS collects, organizes, and analyzes scientific literature, patents, and data covering millions of chemical substances and reactions. It maintains the CAS Registry, the largest database of chemical substances in the world, each identified by a unique CAS Registry Number (CAS RN) used globally by researchers, industry professionals, and regulatory agencies to identify specific chemicals unambiguously. CAS also delivers advanced search and analysis tools such as SciFinder and STN to support scientific discovery, research workflows, and innovation across chemistry and related fields.