Written and maintained by CASRAI Editorial Board
Last updated
SciFinder is the name chemists use for the search products from CAS, the organization, part of the American Chemical Society, that curates chemical information. The current product is called CAS SciFinder, and it sits inside what CAS calls the CAS SciFinder Discovery Platform. If you have been asked “what is SciFinder?” by a supervisor, a librarian or a new lab member, the short answer is a web-based research tool for finding chemical substances, reactions, literature, patents and supplier information in one place. Features and content depend on the license an institution holds.
What is SciFinder?
CAS describes CAS SciFinder as a way to “access the world’s most comprehensive chemical substance and reaction data.” It is a web-based platform, not a single database: it brings together substance records, reaction data, and literature and patent references, and adds analytical and AI-enabled search tools on top. CAS lists these capabilities on its product page:
- Searching by structure, name, CAS Registry Number, or spectra data.
- Finding relevant literature, patents and regulatory information.
- Retrosynthesis predictions in real time.
- Exploring alternative reagents, steps and conditions for a reaction.
- Identifying suppliers and comparing availability and cost.
It is built for people who work with chemical substances and reactions. For a research office, it is one of the discipline-specific discovery tools an institution may license alongside general indexes such as Web of Science and Scopus.
Who runs it and what it covers
CAS, based in Columbus, Ohio, publishes SciFinder. Its own site says that “for over 100 years, CAS has connected the world’s scientific knowledge to accelerate breakthroughs that improve lives.” CAS is part of the American Chemical Society.
The backbone of the platform is the CAS REGISTRY, which CAS defines as “the database of disclosed chemical substances curated from scientific literature and other sources.” CAS’s REGISTRY page puts the size at more than 290 million unique substances (the same page’s body text rounds up to 300+ million; checked 2026-10-28). Every substance in it carries a CAS Registry Number (CAS RN), which CAS describes as a unique and unambiguous identifier for a specific substance. Each number refers to one substance only, which is why a CAS RN is the safest way to search for a compound that has many trade names, synonyms or spellings.
Because the CAS RN is a stable identifier, it is also the link between the platform’s different content types. A substance record, the papers and patents that mention it, and the reactions that make it all hang off the same number.
How people search it
CAS’s product page names four entry points into the data, and these map onto how chemists actually start a question:
- By structure. Useful when you have a drawing of the molecule or a scaffold and want substances, reactions or references that match it.
- By name. A common name, systematic name or trade name, resolved to the registered substance.
- By CAS Registry Number. The unambiguous route when you already have the identifier from a safety data sheet, a supplier catalogue or a paper.
- By spectra data. Searching on analytical data when you have a spectrum and need to identify or confirm a compound.
From a result, the same page describes moving on to related literature and patents, to retrosynthesis predictions, and to supplier availability and cost. Exact screen names, filters and menus are covered in CAS’s own training and help material; CAS lists a demo request, training and customer service on its product page, and the sign-in for licensed users is reached from the CAS site. Access is normally through an institution or an organization with a license.
Searching a chemistry platform shares habits with any literature search. Keep a record of the exact query, note the date, and follow citations forward and backward from the best hits; the citation chaining and snowballing guide covers that technique, and the PubMed Advanced Search Builder guide shows the same discipline on a free database.
Strengths and limits
What the platform is built for
- Unambiguous identification. The CAS RN system gives one number per substance, which removes the guesswork of synonyms.
- Several data types in one place. Substances, reactions, literature, patents, regulatory information and suppliers are searchable together, per CAS’s product description.
- Chemistry-specific search. Structure and spectra searching go beyond what a general keyword index offers.
What to keep in mind
- It is licensed. CAS routes interested organizations to a demo request and customer service, and content and features vary by product license, so what a colleague at another institution sees may differ from what you see.
- It is chemistry-focused. Its subject scope is chemical substances and reactions rather than scholarly literature in general.
- Size figures change. CAS gives slightly different substance counts on one page (more than 290 million, and 300+ million in the body text), so quote the figure with its source and date.
Alternatives and companions
SciFinder is rarely the only tool a research group uses. The table below uses each provider’s own description of what it covers (checked 2026-10-28).
| Tool | What the provider says it is | Access |
|---|---|---|
| CAS SciFinder | Chemical substance and reaction data, with literature, patents, regulatory information and supplier data (CAS) | Licensed; demo request via CAS |
| Reaxys | “comprehensive chemical database and chemistry search engine” combining chemistry data points with AI search and retrosynthesis tools (Elsevier) | Licensed |
| PubMed | Free search service for biomedical and life sciences literature, with more than 40 million citations and abstracts (NCBI, National Library of Medicine) | Free |
| Google Scholar | A way to “broadly search for scholarly literature,” covering articles, theses, books, abstracts and court opinions (Google) | Free |
The tools are different in kind. SciFinder and Reaxys are chemistry platforms organized around substances and reactions. PubMed and Google Scholar are literature search services. For help with the literature side, see using Google Scholar for a literature review, and for how a database’s coverage decisions affect what you can find, journal indexing in DOAJ, Scopus and Web of Science.
Frequently asked questions
What is SciFinder used for?
Finding information about chemical substances and reactions. Per CAS, users search by structure, name, CAS Registry Number or spectra data, then look at related literature, patents, regulatory information, retrosynthesis predictions and suppliers.
Who makes SciFinder?
CAS, based in Columbus, Ohio, which is part of the American Chemical Society.
Is SciFinder free?
CAS offers it as a licensed product, with a demo request and customer service contact. Most users reach it through an institution’s license. Free options for literature searching include PubMed and Google Scholar, though they are not chemistry-structure databases.
What is a CAS Registry Number?
A unique and unambiguous identifier for a specific substance, assigned by CAS. Each number refers to one substance only.
How big is the CAS REGISTRY?
CAS’s REGISTRY page states more than 290 million unique substances, and 300+ million in its body text (checked 2026-10-28).
Where do I find the sign-in?
From the CAS SciFinder pages on cas.org. Licensed users sign in through the route their institution or organization provides.
Sources
- CAS, CAS SciFinder product page: https://www.cas.org/solutions/cas-scifinder-discovery-platform/cas-scifinder (checked 2026-10-28)
- CAS, CAS REGISTRY: https://www.cas.org/cas-data/cas-registry (checked 2026-10-28)
- CAS, About CAS: https://www.cas.org/about (checked 2026-10-28)
- Elsevier, Reaxys: https://www.elsevier.com/products/reaxys (checked 2026-10-28)
- NCBI, About PubMed: https://pubmed.ncbi.nlm.nih.gov/about/ (checked 2026-10-28)
- Google, About Google Scholar: https://scholar.google.com/intl/en/scholar/about.html (checked 2026-10-28)
