Chemical Abstracts Service

Chemical Abstracts Service (CAS) is a division of the American Chemical Society, and produces Chemical Abstracts, and related products. It is located in Columbus, Ohio, USA. Chemical Abstracts is an index of the scientific literature in chemistry and related fields, supplemented by abstracts for almost all the articles. The print format has been published since 1907, but has now been superseded largely by its electronic format. The term "Chemical Abstracts" is often used loosely to apply to all the different files and products, but the different parts now have specific names. In 2007 the Chemical Abstracts Service was designated an ACS National Historical Chemical Landmark in recognition of its significance as the most comprehensive repository of research in chemistry and related sciences.

Files
The two principal databases that are used to support the different products are, CAplus and Registry. CAplus consists of bibliographic information and abstracts for all articles in chemical journals worldwide, and chemistry-related articles from all scientific journals, patents, and other scientific publications. Registry contains information about 27,000,000 organic and inorganic substances, and 57 million DNA sequences. The chemical information is produced by CAS; the sequence information comes from CAS and GenBank, produced by the National Institutes of Health. The chemical information is prepared by the CAS Registry System, which identifies each compound with a specific CAS registry number, index name, and graphic representation of its chemical structure. The assignment of chemical names is done according the chemical nomenclature rules for CA index names, which is slightly different from the internationally standard IUPAC names, according to the rules of IUPAC

Products
The material from these basic and supplementary databases, is searchable in many ways. CAS databases are available via two principal database systems, STN, and Scifinder.

STN
STN is a system operated jointly by CAS and FIZ Karlsruhe, and is intended primarily for information professionals, using a command language interface rather than a graphics interface. In addition to CAS databases, STN also provides access to many other databases, similar to other commercial systems such as Dialog.

SciFinder
SciFinder is a CAS software application designed primarily for use by professional chemists in commercial organizations. Versions for both the Windows and Macintosh operating systems are available. ScifinderScholar is a version without some supplementary features for multi-database searching designed for academic use, and is the product generally found in universities and other academic institutions. They are both designed with a graphics interface, making them particularly suitable for searching the Registry file for chemical structures.