This is a quick orientation and overview of CAS for visitors to our website.

  1. What is CAS?
  2. What is a CAS Registry Number®?
  3. Tell me briefly about CAS products.  
  4. Does CAS offer any free services?
  5. Which CAS product is right for me?
  6. How can a publication get abstracted/indexed by CAS?
  7. Is there a listing of the journals covered by CAS?
  8. Does CAS have a privacy policy?
  9. Who do I contact if I have a question or problem?

1. What is CAS?

A. Chemical Abstracts Service (CAS), a division of the American Chemical Society, is the world’s authority for chemical information. CAS is the only organization in the world whose objective is to find, collect and organize all publicly disclosed substance information. A team of scientists worldwide curates and controls the quality of our databases, which are recognized as the most comprehensive and authoritative by chemical and pharmaceutical companies, universities, government organizations and patent offices around the world. By combining these databases with advanced search and analysis technologies (SciFinder® and STN®), CAS delivers the most current, complete, secure and interlinked digital information environment for scientific discovery.

2. What is a CAS Registry Number?

A. CAS Registry Numbers (often referred to as CAS RNs or CAS Numbers) are universally used to provide a unique, unmistakable identifier for chemical substances. A CAS Registry Number itself has no inherent chemical significance but provides an unambiguous way to identify a chemical substance or molecular structure when there are many possible systematic, generic, proprietary or trivial names.

CAS Registry Numbers are used in many other public and private databases as well as chemical inventory listings and, of course, are included in all CAS-produced databases.

Tell me briefly about CAS products.

A. CAS offers online, Web-based and desktop access to databases covering science, engineering, technology, patents, business information and much more. These products are designed to accommodate a wide range of information needs, whether you are an infrequent searcher who only needs a few quick answers or a professional searcher who requires a more powerful and comprehensive set of search tools.

CAS products are fee-based and generally require you to set up an account.

Does CAS offer any free services?

A. CAS offers Common Chemistry, a free web resource that contains CAS Registry Numbers for approximately 7,900 chemicals of widespread general public interest. Common Chemistry is helpful for those who know either a name or CAS Registry Number of a common chemical and want to pair both pieces of information. CAS has collaborated with Wikipedia in developing this resource and encourages you to use the Wikipedia link (when available) or other sources of general information on chemistry, to learn more about these chemicals.

The CAS Source Index (CASSI) Search Tool is another free online resource intended to support researchers and librarians who need accurate bibliographic information. Use this free tool to quickly identify or confirm journal titles and abbreviations for publications indexed by CAS since 1907, including serial and non-serial scientific and technical publications.  Locate the bibliographic details you need quickly and easily. Search by Title, Abbreviation, CODEN, ISBN, or ISSN.

Which CAS product is right for me?

A. This is a difficult question to quickly answer for new users. It depends on many factors such as how comprehensive your search and answers need to be, your familiarity and experience with online searching, the medium you wish to search in and how frequently you need to search. Of course, cost is also a consideration.

Click here for a quick assessment.

If you are still unsure about the most suitable product for you, the CAS Customer Center will be happy to help you.

  • SciFinder® is a research discovery tool, suitable for both professional searchers and research scientists. You do not have to be an expert searcher to use SciFinder. Many organizations around the world use SciFinder to give their scientists direct access to CAS databases. SciFinder packages and subscriptions can be tailored to smaller groups as well.
  • STN® is the access point to a comprehensive collection of databases covering science, technology, patents, engineering and business information. It is a command-based online service and at least some training in the STN search language is recommended in order to benefit from the precision and power of the system. STN Express® will help make STN searching more efficient and productive.
  • STN on the WebSM brings all the power and functionality of STN to a Web-based system. Structure searching capabilities are included.
  • STN® Easy is a Web-based interface to the most popular databases available on STN. There is no command language to learn, so this service is suited to both infrequent searchers and those who need a simpler, more guided information resource.
  • NCI Global is a web-based product for those involved with regulatory and compliance work.

How can a publication get abstracted/indexed by CAS?

A. We will be delighted to have our selection team of chemists determine whether the journal meets our editorial criteria for abstracting and indexing in the CAS databases.

Publishers interested in having a journal covered in the CAS databases should send either a copy of the first issue (if it is a new publication) or three different and recent issues if it has already been published for some time to:

Chemical Abstracts Service - CAS
Acquisitions / Evaluation Dept.
P.O. Box 3012
Columbus, OH 43210

Electronic journal publishers, please complete and submit the Journal Information Form.

Is there a listing of journals covered by CAS?

A. There is a list of the core journals covered in CAplus. This list includes both the complete and abbreviated journal titles, the CODEN and frequency of publication. Note, however, that this is not the complete list of journals covered by CAS.


8. Does CAS have a privacy policy?

A. Yes. Click here for details.


9. Who do I contact if I have a question or problem?

A. You have several options depending on the nature of your question or concern. Use the following as a guide:

  • Contact the CAS Customer Center for general questions about CAS or STN products. This would include account setup and status, costs, ordering information, obtaining user documentation, etc. The CAS Customer Center can also assist with search strategies and using CAS products. The Center is open 8 a.m.-8 p.m. Eastern Time (Monday-Friday).
  • Contact FIZ AutoDoc when you need to order a copy of a journal article or patent.
  • Contact CAS Client Services if you need confirmation/assignment of CAS Registry Numbers and chemical names or substance identification.
  • For inquiries outside North America, see the list of official CAS/STN representatives who can answer CAS- and STN-related questions.
  • We also recommend trying the site search feature of this website. It doesn't search the fee-based databases for references, CAS Registry Numbers, etc., but it is a useful way to find content on the website.


Contact Us

E-mail   Phone & Fax
help@cas.org   800-753-4227 (North America)
    614-447-3700 (Worldwide)
    614-447-3751 (Fax)
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