What is a CAS no.?
The CAS no. is assigned by the American Chemical Abstracts Service and is a type of an index identifying chemical substances. Each compound has an individual code that allows for its easy classification. Some varieties of the same substance have one CAS no., e.g. products with different concentrations or contamination degree. The CAS database contains information about organic and inorganic compounds, reactants, isotopes, minerals, alloys, etc.
How are CAS no. assigned?
For a new substance, the process of CAS number assignment begins with a submission to the Chemical Abstracts Service. The organization analyses the compound based on the data provided. At this stage, the properties of the submitted product, its structure and other data are reviewed. After the review, a unique CAS no. is assigned and entered into the CAS database. In case of additional modifications, existing items are updated.
What is the structure of CAS no.?
The CAS code consists of several parts – the initial digits constitute a prefix that is used for many substances, although not in every case. Its presence makes it easier to group similar groups of compounds. This part usually contains 2-7 digits. Individual identification elements are separated by dashes. The next part is a unique number, specific for a given compound. The last digit is calculated by a specific algorithm and is known as the check digit.
Are CAS no. globally uniform?
Yes, the CAS number is globally uniform and unique for each registered substance. The consistency of the CAS database is critical for the identification of chemical compounds for scientific and technical purposes, as well as for the safety of humans and the environment.
Do all chemicals have CAS no.?
Not all chemical substances have a CAS number assigned, but the vast majority of them do. In areas where detailed classification of compounds is important, e.g. toxicology, pharmacology, industrial chemistry, a CAS number is assigned to and used for almost every substance used therein.
Can CAS no. change?
Once assigned, the CAS number remains unchanged and is used in every case. Exceptions are possible in situations where an error has been made when entering a new substance.
How to find the CAS no. for a given chemical?
Information about any chemical can be found on the European Chemicals Agency (ECHA) website at: www.echa.europa.eu. The PCC Group Product Portal contains a list of many popular chemicals grouped based on their CAS nos. All products offered by the PCC Group have been described in detail and classified.
Are CAS nos. required in safety data sheets (SDS) and chemical labelling?
Safety data sheets require CAS nos. to standardise the data and facilitate substance identification. Often product labels also include CAS no.
Besides CAS nos., what other chemical identifiers are used?
CAS is one of the most popular identification systems used internationally. Nevertheless, there are also other types of classification of the same compounds, e.g. UN, FEMA, EINECS, HMIS/NFPA, GHS/CLP, SMILES numbers. They are used depending on the need and purpose.
Does the CAS no. provide other information about the properties of chemicals?
The CAS system provides information on some physical and chemical properties but does not provide comprehensive data about a given chemical compound. To obtain data on specific product characteristics, you should use other available databases that are also based on CAS, e.g. PubChem, ChemiSpider, REACH regulations or chemical guides.
Why are CAS no. important?
The use of CAS no. is of great importance in the identification and classification of chemical compounds. It is particularly important when creating product dossier, as well as for safe storage, processing and transportation. The global universality of the CAS system facilitates work and communication in many areas.
Can you search for chemicals by CAS nos.?
The CAS no. is used, among others, to find detailed information about a given chemical substance easily and quickly. Based on the CAS no., you can easily search for compounds in various databases, catalogues, publications and documentation.
