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CAS Registry
Numbers (CAS RN) 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
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The CAS Registry is an authoritative collection of disclosed chemical substance information. It identifies more than 204 million unique organic and inorganic substances and 69 million protein and DNA sequences, plus additional information about each substance. It is updated with around 15,000
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Historically, chemicals have been identified by a wide variety of synonyms. One of the biggest challenges in the early development of substance indexing, a task undertaken by the
Chemical Abstracts Service, was in identifying if a substance in literature was new or if it had been previously
580:
Jacobs, Andrea; Williams, Dustin; Hickey, Katherine; Patrick, Nathan; Williams, Antony J.; Chalk, Stuart; McEwen, Leah; Willighagen, Egon; Walker, Martin; Bolton, Evan; Sinclair, Gabriel; Sanford, Adam (13 June 2022).
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Jacobs, Andrea; Williams, Dustin; Hickey, Katherine; Patrick, Nathan; Williams, Antony J.; Chalk, Stuart; McEwen, Leah; Willighagen, Egon; Walker, Martin; Bolton, Evan; Sinclair, Gabriel; Sanford, Adam (13 May 2022).
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of a chemical into a computer-searchable table, which provided a basis for the service that listed each chemical with its CAS Registry Number, the CAS Chemical
Registry System, which became operational in 1965.
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A CAS RN is separated by hyphens into three parts, the first consisting from two up to seven digits, the second consisting of two digits, and the third consisting of a single digit serving as a
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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.
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The check digit is found by taking the last digit times 1, the preceding digit times 2, the preceding digit times 3 etc., adding all these up and computing the sum
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76:. This registry includes all substances described since 1957, plus some substances from as far back as the early 1800s; it is a
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additional new substances daily. A collection of almost 500 thousand CAS registry numbers are made available under a
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do not receive different CAS RNs (liquid water and ice both have 7732-18-5), but different crystal structures do (
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discovered. Well-known chemicals may additionally be known via multiple generic, historical, commercial, and/or
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728:"CAS Common Chemistry in 2021: Expanding Access to Trusted Chemical Information for the Scientific Community"
583:"CAS Common Chemistry in 2021: Expanding Access to Trusted Chemical Information for the Scientific Community"
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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.
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Commonly encountered mixtures of known or unknown composition may receive a CAS RN; examples are
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based on structure alone was not universally useful. An algorithm was developed to translate the
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Occasionally whole classes of molecules receive a single CAS RN: the class of enzymes known as
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databases today allow searching by CAS Registry Number, and it is used as a global standard.
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530:"CAS Common Chemistry expands collection of publicly available chemical information"
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described in the open scientific literature, in order to index the substance in the
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124:), so they do not contain any information about the structures themselves the way
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181:. This format gives CAS a maximum capacity of 1,000,000,000 unique numbers.
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Screenshot of the CAS Common
Chemistry database with information about
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National
Induscctrial Chemicals Notification and Assessment Scheme.
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National
Industrial Chemicals Notification and Assessment Scheme.
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Common
Chemistry via Australian Inventory of Chemical Substances
100:, mixtures, and nonstructurable materials (UVCBs, substances of
812:"ESIS : European chemical Substances Information System"
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NIOSH Pocket Guide to
Chemical Hazards, index of CAS numbers
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has 7440-47-3, the trivalent Cr(III) has 16065-83-1 and the
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Search Tool of
Australian Inventory of Chemical Substances
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are discerned by their oxidation state, e.g. the element
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or structure, the following free resources can be used:
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To find the CAS number of a compound given its name,
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https://www.cas.org/content/chemical-substances/faqs
864:"HSNO Chemical Classification Information Database"
651:Canadian Centre for Occupational Health and Safety
294:Canadian Centre for Occupational Health and Safety
368:International Union of Pure and Applied Chemistry
308:European chemical Substances Information System
432:"CAS Registry Number Verified Partner Program"
8:
975:ChemSub Online (Multilingual chemical names)
732:Journal of Chemical Information and Modeling
587:Journal of Chemical Information and Modeling
451:
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208:are assigned discrete CAS Registry Numbers:
810:European Commission Joint research Centre.
676:United States National Library of Medicine
300:United States National Library of Medicine
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614:
116:iological origin). CAS RNs are generally
373:List of CAS numbers by chemical compound
860:Environmental Risk Management Authority
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358:(EINECS and ELINCS, European Community)
318:Environmental Risk Management Authority
224:-epinephrine has 150-05-0, and racemic
970:NCI/CADD Chemical Identifier Resolver
785:"AICS Detailed Help / Guidance Notes"
7:
917:"CompTox Chemicals Dashboard | Home"
188:10. For example, the CAS number of
837:Library & Information Centre.
140:license at ACS Commons Chemistry.
25:
556:"CAS Surveys Its First 100 Years"
325:USEPA CompTox Chemicals Dashboard
947:, by Chemical Abstracts Service
839:"Finding a CAS Registry Number"
560:Chemical & Engineering News
421:, by Chemical Abstracts Service
351:Dictionary of chemical formulas
554:Shively, Eric (11 June 2007).
1:
112:omplex reaction products, or
62:unique identification number
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995:Chemical numbering schemes
312:Royal Society of Chemistry
66:Chemical Abstracts Service
1000:American Chemical Society
701:American Chemical Society
486:"CAS Registry and CASRNs"
482:American Chemical Society
457:"CAS Content: Substances"
341:Beilstein Registry Number
273:hexavalent Cr(VI) species
241:in general is 7440-44-0,
230:-epinephrine has 329-65-7
68:(CAS) in the US to every
945:CAS registry description
744:10.1021/acs.jcim.2c00268
599:10.1021/acs.jcim.2c00268
412:CAS registry description
298:ChemIDplus Advanced via
155:systematic nomenclature
965:NIST Chemistry WebBook
388:Registration authority
280:alcohol dehydrogenases
45:
680:"ChemIDplus Advanced"
292:CHEMINDEX Search via
108:ariable composition,
52:(also referred to as
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960:CAS Common Chemistry
346:Chemical file format
364:(Enzyme Commission)
336:Academic publishing
310:via the website of
50:CAS Registry Number
27:Chemical identifier
1005:Unique identifiers
891:"AICS Search Tool"
705:"Substance Search"
655:"CHEMINDEX Search"
417:2008-07-25 at the
159:structural formula
70:chemical substance
64:, assigned by the
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818:on 1 January 2014
738:(11): 2737–2743.
593:(11): 2737–2743.
265:chemical elements
256:(12627-53-1) and
245:is 7782-42-5 and
78:chemical database
16:(Redirected from
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74:CAS Registry
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516:www.cas.org
461:www.cas.org
258:mustard oil
216:epinephrine
196:Granularity
179:check digit
122:check digit
88:compounds,
989:Categories
926:14 October
399:References
378:MDL number
233:Different
104:nknown or
58:CAS Number
18:CAS number
770:248778162
607:1549-9596
466:10 August
393:UN number
362:EC number
86:inorganic
762:35559614
625:35559614
565:16 April
539:17 March
438:4 August
415:Archived
330:See also
269:chromium
243:graphite
138:CC BY-NC
120:(with a
94:isotopes
90:minerals
38:caffeine
953:formula
901:11 July
874:14 July
844:11 July
822:11 July
753:9199008
685:28 June
660:13 July
616:9199008
496:25 July
383:PubChem
247:diamond
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239:carbon
235:phases
186:modulo
170:Format
126:SMILES
98:alloys
54:CAS RN
766:S2CID
434:. CAS
263:Some
190:water
130:InChI
928:2021
903:2009
876:2009
846:2009
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758:PMID
712:2009
687:2021
662:2009
621:PMID
603:ISSN
567:2024
541:2021
498:2009
468:2020
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128:and
84:and
748:PMC
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611:PMC
595:doi
534:CAS
356:EC#
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
