CAS number

From WolfWikis

CAS numbers (also known as registry numbers) are unique identifiers for chemicals. They have the form of three numbers, separated by dashes:

## - ## - #

Examples

• Acetylsalicylic acid - 50-78-2
• Caffeine - 58-08-2
• Gold - 7440-57-5
• Phenylhydrazone - 3713-25-5

It is highly recommended that you use CAS numbers to conduct searches in chemistry databases and books instead of common names, because a given chemical can have dozens of names and synonyms. The book or database you're searching in may not use the same name for a chemical that you do, so you won't be able to find it. CAS numbers are consistent across different sources.