CAS Registry Number

A CAS Registry Number, also referred to as CASRN or CAS Number, is an unique numerical identifier assigned by Chemical Abstracts Service (CAS - a division of the American Chemical Society) to every chemical substance described in the open scientific literature. 

A CAS Registry Number itself has no inherent chemical significance but provides an unambiguous way to identify a chemical substance or molecular structure when there are many possible systematic, generic, proprietary or trivial names.

Source: CAS 


  • CAS
  • CAS RN
  • CAS Number