CAS registry number
” (For more information, see What does a CAS Registry Number look like?) The rules of chemical nomenclature frequently change and each chemical substance is liable to have several names: i.e. trade or brand name(s); generic or common name(s); trivial or semisystematic name(s); and systematic or IUPAC name(s). For example, Tylenol is a brand name for acetaminophen which is itself a trivial name. The systematic name for this analgesic compound is Acetamide, N-(4-hydroxyphenyl)-. Another systematic name for this same compound is 4′-Hydroxyacetanilide. There is just one CAS registry number which is 103-90-2. Even if other names are created for this compound, the registry number will remain unchanged. There is no structural significance to the registry number – it is simply an identifier. The most efficient and complete way to search for chemical substances in the Chemical Abstracts Online database is to use the CAS registry number(s). A registry number may be searched as if it were a word,
CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. They are also referred to as CAS numbers, CAS RNs or CAS #s. Chemical Abstracts Service (CAS), a division of the American Chemical Society, assigns these identifiers to every chemical that has been described in the literature. The intention is to make database searches more convenient, as chemicals often have many names. Almost all molecule databases today allow searching by CAS number. As of December 2008, there were more than 40 million organic and inorganic substances and more than 60 million sequences in the CAS registry.[1] Around 50,000 new numbers are added each week. CAS also maintains and sells a database of these chemicals, known as the CAS registry.
