CAS no. and EC no.
A CAS number (Chemical Abstracts Service number) is a registration number for chemicals. It functions as an international identification number for chemical substances.
EC numbers are used for chemical substances on the market within the EU. It is the number of a substance in either Einecs, Elincs or the No-Longer Polymers List. Einecs is a European list of those substances considered to exist in the common market between 1 January 1971 and 18 September 1981. Elincs is a European list of notified new substances. The No-longer Polymers List is a European list of substances that were on the common market between 18 September 1981 and 31 October 1993 and at the time were regarded as polymers, but are no longer regarded as such.
The number is made up of seven digits according to the pattern xxx-xxx-x. Einecs numbers start with number 200-001-8. Elincs numbers start with 400-010-9 and No-longer Polymers List numbers start with 500-001-0.