Chemical Abstracts Services Registry Number CAS-RN

One or more national standardization organizations and the International Organization of Standardization approve standard names. The chemical names are either according to the rules of the International Union of Pure and Applied Chemistry or according to Chemical Abstracts. The so-called Chemical Abstracts Services Registry Number (CAS-RN) is a number that makes it easy to find the product or chemical in databases from Chemical Abstracts. The standard names are regarded as ordinary nouns, but the pesticide products are sold under a trade name that is treated as a proper name with a capital initial letter. We use the various names of a fungicide as an example ... 

The table lists the name normally used in the Handbook of Chemistry and Physics, followed by additional names and acronyms by which the substance is known. In many cases the primary name given here is different from that used in the NTP report however, names used in the NTP report appear in the Other Names column. The Chemical Abstracts Service Registry Number (CAS RN), given in the last column, is taken from the NTP report. Extensive details on each substance are given in the reference. 

CAS RN The Chemical Abstracts Service Registry Number for the compound. 

CAS Registry Number Index Lists compounds by Chemical Abstracts Service Registry Number. Note there is some redundancy in this index, because many compounds have several Registry Numbers associated with them. Thus the CAS RN in a table entry may differ from the CAS RN that points to it in the index. For example, CAS RN 1319-77-3 in the index points to all three cresol isomers, each of which has its own specific CAS RN. 

CAS Registry Number Chemical Abstracts Service Registry Number. An asterisk following the CAS RN for a hydrate indicates that the number refers to the anhydrous compound. In most cases the generic CAS RN for the compound is given rather than the number for a specific crystalline form or mineral. 

For some time registry numbers seemed to be a solution to the problem, at least for the bench chemist and the layman, in that a new registry number is attributed to a compound when it is first registered by Chemical Abstracts Service (CAS RN) or Beilstein (BRN). This number then serves as the compound s unique ID. This procedure leaves the agency with the problem to compare a seemingly new compound to all those already present in the database. As a further principal limitation, a RN is not available for an unpublished compound. Furthermore, registry numbers can also be given to mixtures thus one compound may also have several RNs. 

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