The Chemical Abstracts Service is part of the American Chemical
Society and maintains a database of chemical compounds and
sequences. The CAS database currently contains over 55 million
different organic and inorganic chemical compounds. Each CAS
entry is identified by their CAS Registry Number, or CAS RN for
short. CAS Numbers themselves are up to 10 digits long using the
format xxxxxxx-yy-z. They are assigned to a compound as the CAS
registers a new compound. The number has no significance to the
chemistry, structure or chemical nature of the molecule. The CAS
Number of a compound is a useful way to identify a chemical over
its name. For example, the compound CAS 64-17-5 refers to
ethanol. Ethanol is also known as ethyl alcohol, ethyl hydrate,
absolute alcohol, grain alcohol, hydroxyethane. The CAS number
is the same for all these names. The CAS Number can also be used
to distinguish between stereoisomers of a compound. Glucose is a
sugar molecule that has two forms: D-glucose and L-glucose.
D-glucose is al