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Digits in three hyphen-separated groups, the last a single check digit.
Also known as: CAS number, CASRN, Chemical Abstracts number, Registry number
A CAS number identifies a substance as registered, not as characterised: the number itself encodes nothing about the structure and is assigned sequentially. Its final digit is a checksum, so a mistyped number is usually detectable without a lookup.
Denotes a unique identifier assigned by CAS to a chemical substance, in the form of two to seven digits, two digits and a check digit.
Contexts: Laboratory
Carries no structural information: numbers are assigned in registration order, so adjacent numbers are unrelated substances.
Contexts: Laboratory
Ends in a check digit computed from the preceding digits, which detects most transcription errors without a database lookup.
Contexts: Laboratory
A row of digits divided by two hyphens into a long group, a two-digit group and a single final digit.