RN CAS Registry Number

(a limit field)

rn=50-*

62-53-3 in rn

999* in rn

100-5* in rn

This is one of the fields contained within the Substance Identifiers and Basic Chemistry superfield (ZID) which itself is associated with the Substance Identifiers and Basic Chemistry message field (ID).

The Chemical Abstracts Service (CAS) Registry Number is a number sequence of up to 9 digits adopted by the Chemical Abstracts Service (American Chemical Society, Columbus, Ohio, USA) to uniquely identify specific chemical substances. The number contains no information relating to the chemical structure of a substance and is a catalogue number relating to one of the 13 million or so unique chemical substances recorded in the Chemical Abstracts Registry. New numbers are assigned sequentially to each new compound identified by the Chemical Abstracts Service.

The format is: XXXXXX-XX-X. CAS numbers are searched and displayed in a hyphenated format without leading zeros. Occasionally, this field will contain two or more such numbers with some explanatory text indicating, perhaps, different physical, chemical or steroechemical forms of the same basic substance. This field occurs in every DOSE record.

You may use truncation (as shown above) or wild cards to broaden your search.

Every DOSE record has a CAS number associated with it. Using the CAS number is a good way of identifying and finding a DOSE substance record.