| − | CAS numbers identify each unique chemical compound, polymer, biological sequence, mixtures and alloy. | + | A '''Chemical Abstracts Service number''' (CAS number) is a number which is used to identify each unique chemical compound, polymer, biological sequence, mixture and alloy. |
| − | The [[Chemical Abstracts Service]] (CAS), a division of the American Chemical Society, assigns unique identifiers to every different chemical. Most molecule databases today permit searching for a compound by entering its CAS number. There are over 30 million CAS numbers as of May 2007. | + | The [[Chemical Abstracts Service]], a division of the [[American Chemical Society]], assigns unique identifiers to every different chemical. Most molecule databases today permit searching for a compound by entering its CAS number. There are over 30 million CAS numbers as of May 2007. |