What does the CAS number tell me?

Often, at first glance, it is not possible to see whether items from different suppliers are the same product. Just by the name (keyword trivial names, long lasting IUPAC names, other language names) a statement is often not possible. Even the empirical formula is not a solution since it can be identical for several substances and further physical parameters have to be used for the analysis The CAS number clearly indicates which chemical compound is involved. It distinguishes between the different salt forms (sodium salt / potassium salt / monohydrate / decahydrate / hydrochloride etc.) and between stereoisomers. For non-chemists, too, the CAS number therefore allows a simple and unambiguous assignment / identification of the chemical substance offered.