Numéro CAS – CAS Registry Number
9 février 2017 par maty185
Source Wikipedia
Le numéro CAS (CAS number ou CAS registry number en anglais) d’une substance chimique, polymère, séquence biologique et alliage est son numéro d’enregistrement unique auprès de la banque de données de Chemical Abstracts Service (CAS), une division de l’American Chemical Society (ACS). Le CAS assigne ces numéros à chaque substance chimique qui a été décrite dans la documentation. De plus, CAS maintient et commercialise une base de données de ces substances, le CAS Registry.
Pour accéder aux substances chimiques disponibles sur ce Wikipédia à partir de leur numéro CAS, choisir Liste des numéros CAS.
Sommaire
Description
En 2014, plus de 90 millions de substances organiques et inorganiques ont reçu un numéro CAS1. Environ 4 000 nouveaux numéros sont ajoutés chaque jour. Le but est de faciliter les recherches dans les bases de données, vu que les produits chimiques ont souvent différents noms. Presque toutes les bases de données de molécules actuelles permettent une recherche par numéro CAS.
Les numéros CAS sont attribués dans un ordre croissant et n’ont pas de signification particulière. Une entrée se décline en trois parties séparées par un tiret. La première peut contenir jusqu’à sept chiffres, la deuxième contient deux chiffres, la troisième contient un chiffre pour la somme de contrôle. Cette dernière se calcule en prenant le 1er chiffre fois 1, le 2e fois 2, et ainsi de suite en partant de l’avant-dernier (de droite à gauche). La somme de ces résultats intermédiaires est ensuite additionnée modulo 10. Par exemple, le numéro CAS de l’eau est : sa somme de contrôle vaut (8×1 + 1×2 + 2×3 + 3×4 + 7×5 + 7×6) mod 10 = 105 mod 10 = 5.
Les différents isomères d’une molécule ont un numéro CAS différent : le D–glucose a , le L-glucose a , le α-D-glucose a , etc. À l’inverse parfois, une classe complète de molécules reçoit un seul numéro : le groupe des alcools déshydrogénases a .
Lors de recherche par numéro CAS dans les bases de données, il est utile d’inclure le numéro de composés proches. Par exemple, pour chercher de l’information sur la cocaïne ( ), il faut aussi chercher pour chlorhydrate de cocaïne ( ), puisque c’est sous cette forme que la cocaïne est utilisée en tant que drogue.
Ressources
Pour retrouver le numéro CAS d’un composé à partir de son nom, de sa formule chimique ou de sa structure, les ressources libres[réf. souhaitée] suivantes sont disponibles :
- (en) ChemIDplus [archive] (NIH) ;
- (en) Chemistry WebBook [archive] (NIST) ;
- (en) NCI Database Browser [archive] ;
- (en) ChemSub Online: Portal and Information System on Chemical Substances [archive] (avec noms de substances en français) ;
- (en) ChemExper [archive].
Références
- (en) « Chemical Abstracts Service » [archive] (consulté le 4 novembre 2014).
Voir aussi
Articles connexes
- Numéro EINECS
- Numéro ELINCS
- Numéro NSC
- Liste des numéros ONU
- Liste de composés organiques
- Liste de composés inorganiques
Liens externes
- (en) « Chemical Abstracts Service » [archive]
- (en) « CAS Registry and CAS Registry Number FAQs » [archive] (description du registre CAS)
https://fr.wikipedia.org/wiki/Num%C3%A9ro_CAS
A CAS Registry Number,[1] also referred to as CASRN or CAS Number, is a unique numerical identifier assigned by Chemical Abstracts Service (CAS) to every chemical substance described in the open scientific literature (currently including those described from at least 1957 through the present), including organic and inorganic compounds, minerals, isotopes, alloys and nonstructurable materials (UVCBs, of unknown, variable composition, or biological origin).[2]
The Registry maintained by CAS is an authoritative collection of disclosed chemical substance information. Currently the CAS Registry identifies more than 102 million organic and inorganic substances and 66 million protein and DNA sequences,[3] plus additional information about each substance. The Registry is updated with an approximate 15,000 additional new substances daily.[4]
Contents
Use
Historically, chemicals have been identified by a wide variety of synonyms. Frequently these are arcane and constructed according to regional naming conventions relating to chemical formulae, structures or origins. Well-known chemicals may additionally be known via multiple generic, historical, commercial, and/or black-market names.
CAS Registry Numbers are simple and regular, convenient for database searches. They offer a reliable, common and international link to every specific substance across the various nomenclatures and disciplines used by branches of science, industry, and regulatory bodies. Almost all molecule databases today allow searching by CAS Registry Number.
On the other hand, CASRNs are not related to chemistry, are proprietary and unrelated to any previous systems, and do not readily form phonetic analogs or synonyms.
Format
A CAS Registry Number has no inherent meaning but is assigned in sequential, increasing order when the substance is identified by CAS scientists for inclusion in the CAS REGISTRY database.
A CASRN is separated by hyphens into three parts, the first consisting from two up to seven digits,[5] the second consisting of two digits, and the third consisting of a single digit serving as a check digit. The check digit is found by taking the last digit times 1, the previous digit times 2, the previous digit times 3 etc., adding all these up and computing the sum modulo 10. For example, the CAS number of water is 7732-18-5: the checksum 5 is calculated as (8×1 + 1×2 + 2×3 + 3×4 + 7×5 + 7×6) = 105; 105 mod 10 = 5.
Granularity
- Stereoisomers and racemic mixtures are assigned discrete CAS Registry Numbers: L-epinephrine has 51-43-4, D-epinephrine has 150-05-0, and racemic DL-epinephrine has 329-65-7
- Different phases do not receive different CASRNs (liquid water and ice both have 7732-18-5), but different crystal structures do (carbon in general is 7440-44-0, graphite is 7782-42-5 and diamond is 7782-40-3)
- Commonly encountered mixtures of known or unknown composition may receive a CASRN; examples are Leishman stain (12627-53-1) and mustard oil (8007-40-7).
- Some metals are discerned by their oxidation state, e.g. the element chromium has 7440-47-3, the trivalent Cr(III) has 16065-83-1 and the hexavalent Cr(VI) ion has 18540-29-9.
- Occasionally whole classes of molecules receive a single CASRN: the class of enzymes known as alcohol dehydrogenases has 9031-72-5.
Ownership
The assigning agency, Chemical Abstracts Service (CAS) is a division of the American Chemical Society (ACS); CAS information is copyrighted by the ACS. Users wishing to incorporate CAS Registry Numbers into databases should refer to CAS policy:
A User or Organization may include, without a license and without paying a fee, up to 10,000 CAS Registry Numbers or CASRNs in a catalog, web site, or other product for which there is no charge. The following attribution should be referenced or appear with the use of each CASRN: CAS Registry Number is a Registered Trademark of the American Chemical Society.[6]
CAS Registry Number search engine
- CHEMINDEX Search via Canadian Centre for Occupational Health and Safety[7]
- ChemIDplus Advanced via United States National Library of Medicine[8]
- Common Chemistry TM[9] via Australian Inventory of Chemical Substances[10]
- European chemical Substances Information System[11] via the website of Royal Society of Chemistry[12]
- HSNO Chemical Classification Information Database via Environmental Risk Management Authority[13]
- Search Tool of Australian Inventory of Chemical Substances[14]
See also
- List of CAS numbers by chemical compound
- International Union of Pure and Applied Chemistry
- Academic publishing
- Beilstein Registry Number
- Chemical database
- Chemical file format
- Dictionary of chemical formulas
- EC number (Enzyme Commission)
- EC# (EINECS and ELINCS, European Community)
- Identifier
- International Chemical Identifier (InChI)
- MDL number
- PubChem
- Registration authority
- SMILES
- UN number
Notes
- CAS registry description, by Chemical Abstracts Service
- American Chemical Society. « CAS Registry and CASRNs ». Retrieved 25 July 2009.
- CAS database counter (updated daily).
- Chemical Substances – CAS REGISTRY
- 2014-06-18, https://www.cas.org/content/chemical-substances/faqs
- American Chemical Society (CAS) (2009-06-18). « CAS Information Use Policies (effective July 2, 2009) ». Retrieved 2010-02-10.
- Canadian Centre for Occupational Health and Safety. « CHEMINDEX Search ». Retrieved 13 July 2009.
- United States National Library of Medicine. « Advanced ». Retrieved 1 December 2009.
- American Chemical Society. « Substance Search ». Retrieved 8 July 2009.
- National Industrial Chemicals Notification and Assessment Scheme. « AICS Detailed Help / Guidance Notes ». Archived from the original on 9 July 2009. Retrieved 8 July 2009.
- European Commission Joint research Centre. « ESIS : European chemical Substances Information System ». Retrieved 11 July 2009.
- Library & Information Centre. « Finding a CAS Registry Number ». Retrieved 11 July 2009.
- Environmental Risk Management Authority. « HSNO Chemical Classification Information Database ». Archived from the original on 11 July 2009. Retrieved 14 July 2009.
- National Industrial Chemicals Notification and Assessment Scheme. « AICS Search Tool ». Archived from the original on 14 May 2009. Retrieved 11 July 2009.
External links
Wikidata has the property: CAS Registry Numbers (P231) (see uses) |
- CAS registry description, by Chemical Abstracts Service
To find the CAS number of a compound given its name, formula or structure, the following free resources can be used: