CAS Number (Chemical Abstract Service Number)
A CAS Number (Chemical Abstracts Service) is a Registry Number which is a unique identifier for a certain chemical element, substance, or compound regardless of how many names it has (IUPAC and other names).
Also, from a safety and inventory perspective, the CAS # is a great registry reference for indexed chemicals.
For instance, in year 2015, we know there were almost 101 million unique chemical substances indexed by CAS. In addition to 66 million protein and nucleic acid sequences.
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