CAS registry number
Encyclopedia
CAS Registry Numbers
are unique numerical identifier
s assigned by the "Chemical Abstracts Service
" to
every chemical described in the
open scientific literature (currently including those described from at least 1957 through the present) and including
element
s,
isotopes,
organic and
inorganic compounds,
organometallics
,
metals,
alloys,
coordination compounds,
minerals, and
salts;
as well as
standard mixtures,
compounds
,
polymer
s;
biological sequences including
proteins &
nucleic acids;
nuclear particles, and
nonstructurable materials (aka 'UVCB's- i.e., materials of Unknown, Variable Composition, or Biological origin).
They are also referred to as CAS RNs, CAS Numbers, etc.
Currently the CAS Registry identifies more than 56 million organic and inorganic substances and 62 million sequences, plus additional information about each substance;
and the Registry is updated with an approximate 12,000 additional new substances daily.
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.
For example, Hoffman's "∂-Lysergsäure-Diethylamid", indexed by the CAS under the name "Ergoline-8-carboxamide, 9,10-didehydro-N,N-diethyl-6-methyl-, (8β)"-
and also known from the Merck Manual synthesis by names such as "9,10-Didehydro-N,N-diethyl-6-methylergoline-8β-carboxamide"- -
became most conveniently and discretely known as LSD-25 during initial pharmaceutical investigations.
But then during Sandoz' international promotion of the drug, it was subsequently labeled "Delysid" in the west.
After 1963 Delysid attracted many additional, more colorful marketing names, initially confusing law enforcement and lay persons. Since 1989 LSD is again labeled for western research uses, currently available under another, historic trade name: "Lysergide".
On the other hand, CAS Numbers are not related to chemistry, are unrelated to any previous systems, and do not readily form phonetic analogs or synonyms. The 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.
A CAS Registry Number is separated by hyphens into three parts, the first consisting of up to 7 digits, 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.
has 50-99-7, L-glucose
has 921-60-8, α-D-glucose
has 26655-34-5, etc.
• Occasionally whole classes of molecules receive a single CAS number: the group of enzymes known as alcohol dehydrogenase
s has 9031-72-5.
• A standard mixture of otherwise-identified compounds may receive a corporate CAS number; One example is mustard oil
(8007-40-7).
is a function of the American Chemical Society (ACS)
;
CAS information is copyrighted by the ACS. Users wishing to incorporate CAS Numbers into databases should refer to CAS policy:
. Thus formaldehyde was potentially the first compound to receive a CAS registry number.
To find the CAS number of a compound given its name, formula
or structure, the following free resources can be used:
are unique numerical identifier
Identifier
An identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, physical [countable] object , or physical [noncountable] substance...
s assigned by the "Chemical Abstracts Service
Chemical Abstracts Service
Chemical Abstracts is a periodical index that provides summaries and indexes of disclosures in recently published scientific documents. Approximately 8,000 journals, technical reports, dissertations, conference proceedings, and new books, in any of 50 languages, are monitored yearly, as are patent...
" to
every chemical described in the
open scientific literature (currently including those described from at least 1957 through the present) and including
element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
s,
isotopes,
organic and
inorganic compounds,
organometallics
Organometallic chemistry
Organometallic chemistry is the study of chemical compounds containing bonds between carbon and a metal. Since many compounds without such bonds are chemically similar, an alternative may be compounds containing metal-element bonds of a largely covalent character...
,
metals,
alloys,
coordination compounds,
minerals, and
salts;
as well as
standard mixtures,
compounds
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
,
polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
s;
biological sequences including
proteins &
nucleic acids;
nuclear particles, and
nonstructurable materials (aka 'UVCB's- i.e., materials of Unknown, Variable Composition, or Biological origin).
They are also referred to as CAS RNs, CAS Numbers, etc.
Use
The Registry maintained by CAS is an authoritative collection of disclosed chemical substance information.Currently the CAS Registry identifies more than 56 million organic and inorganic substances and 62 million sequences, plus additional information about each substance;
and the Registry is updated with an approximate 12,000 additional new substances daily.
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.
For example, Hoffman's "∂-Lysergsäure-Diethylamid", indexed by the CAS under the name "Ergoline-8-carboxamide, 9,10-didehydro-N,N-diethyl-6-methyl-, (8β)"-
and also known from the Merck Manual synthesis by names such as "9,10-Didehydro-N,N-diethyl-6-methylergoline-8β-carboxamide"- -
became most conveniently and discretely known as LSD-25 during initial pharmaceutical investigations.
But then during Sandoz' international promotion of the drug, it was subsequently labeled "Delysid" in the west.
After 1963 Delysid attracted many additional, more colorful marketing names, initially confusing law enforcement and lay persons. Since 1989 LSD is again labeled for western research uses, currently available under another, historic trade name: "Lysergide".
On the other hand, CAS Numbers are not related to chemistry, are unrelated to any previous systems, and do not readily form phonetic analogs or synonyms. The 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.
Format
A CAS 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 CAS Registry Number is separated by hyphens into three parts, the first consisting of up to 7 digits, the second consisting of two digits, and the third consisting of a single digit serving as a check digit
Check digit
A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. It consists of a single digit computed from the other digits in the message....
.
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
Modular arithmetic
In mathematics, modular arithmetic is a system of arithmetic for integers, where numbers "wrap around" after they reach a certain value—the modulus....
10. For example, the CAS number of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
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.
Standardization of Complexity
• Isomers of a molecule are assigned discrete CAS numbers: D-glucoseGlucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
has 50-99-7, L-glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
has 921-60-8, α-D-glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
has 26655-34-5, etc.
• Occasionally whole classes of molecules receive a single CAS number: the group of enzymes known as alcohol dehydrogenase
Alcohol dehydrogenase
Alcohol dehydrogenases are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide...
s has 9031-72-5.
• A standard mixture of otherwise-identified compounds may receive a corporate CAS number; One example is mustard oil
Mustard oil
The term mustard oil is used for three different oils that are made from mustard seeds:*A fatty vegetable oil resulting from pressing the seeds,...
(8007-40-7).
Ownership
The assigning agency, Chemical Abstracts Service (CAS)Chemical Abstracts Service
Chemical Abstracts is a periodical index that provides summaries and indexes of disclosures in recently published scientific documents. Approximately 8,000 journals, technical reports, dissertations, conference proceedings, and new books, in any of 50 languages, are monitored yearly, as are patent...
is a function of the American Chemical Society (ACS)
American Chemical Society
The American Chemical Society is a scientific society based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has more than 161,000 members at all degree-levels and in all fields of chemistry, chemical...
;
CAS information is copyrighted by the ACS. Users wishing to incorporate CAS 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.
CAS number search engine
- CHEMINDEX Search via Canadian Centre for Occupational Health and SafetyCanadian Centre for Occupational Health and SafetyThe Canadian Centre for Occupational Health and Safety is a Crown corporation owned by the Government of Canada.CCOHS functions as the primary national agency in Canada for the advancement of safe and healthy workplaces and preventing work-related injuries, illnesses and deaths...
- ChemIDplus Advanced via United States National Library of MedicineUnited States National Library of MedicineThe United States National Library of Medicine , operated by the United States federal government, is the world's largest medical library. Located in Bethesda, Maryland, the NLM is a division of the National Institutes of Health...
- Common Chemistry TM via Australian Inventory of Chemical Substances
- European chemical Substances Information System via the website of Royal Society of ChemistryRoyal Society of ChemistryThe Royal Society of Chemistry is a learned society in the United Kingdom with the goal of "advancing the chemical sciences." It was formed in 1980 from the merger of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society and the Society for Analytical Chemistry with a new...
- HSNO Chemical Classification Information Database via Environmental Risk Management AuthorityEnvironmental Risk Management AuthorityThe Environmental Risk Management Authority is a New Zealand government agency which controls the introduction of hazardous substances and new organisms....
- Search Tool of Australian Inventory of Chemical Substances
Trivia
The lowest numeric CAS registry number is 50-00-0 corresponding to formaldehydeFormaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...
. Thus formaldehyde was potentially the first compound to receive a CAS registry number.
See also
- International Union of Pure and Applied ChemistryInternational Union of Pure and Applied ChemistryThe International Union of Pure and Applied Chemistry is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science . The international headquarters of IUPAC is located in Zürich,...
- Academic publishingAcademic publishingAcademic publishing describes the subfield of publishing which distributes academic research and scholarship. Most academic work is published in journal article, book or thesis form. The part of academic written output that is not formally published but merely printed up or posted is often called...
- Beilstein Registry NumberBeilstein Registry NumberThe Beilstein Registry Number is a way of identifying compounds similar to the CAS registry number. It is the unique identifier for compounds in the Beilstein database....
- Chemical databaseChemical databaseA chemical database is a database specifically designed to store chemical information. This information is about chemical and crystal structures, spectra, reactions and syntheses, and thermophysical data.- Chemical structures :...
- Chemical file formatChemical file formatThis article discusses some common molecular file formats, including usage and converting between them.-Distinguishing formats:Chemical information is usually provided as files or streams and many formats have been created, with varying degrees of documentation. The format can be found by three...
- Dictionary of chemical formulasDictionary of chemical formulasThis is a list of chemical compounds with chemical formulas and CAS numbers, indexed by formula. This complements alternative listings to be found at list of inorganic compounds, list of organic compounds and inorganic compounds by element.-Tables to be merged:...
- EC numberEC numberThe Enzyme Commission number is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze....
(Enzyme Commission) - EC#EC-NoThe European Commission number, or EC number, also known as EC-No and EC#, is the seven-digit code that is assigned to chemical substances that are commercially available within the European Union...
(EINECS and ELINCS) - IdentifierIdentifierAn identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, physical [countable] object , or physical [noncountable] substance...
- International Chemical IdentifierInternational Chemical IdentifierThe IUPAC International Chemical Identifier is a textual identifier for chemical substances, designed to provide a standard and human-readable way to encode molecular information and to facilitate the search for such information in databases and on the web...
(InChI) - MDL number
- PubChemPubChemPubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information , a component of the National Library of Medicine, which is part of the United States National Institutes of Health . PubChem can...
- Registration authorityRegistration authorityA registration authority or maintenance agency is a body given the responsibility of maintaining lists of codes under international standards and issuing new codes to those wishing to register them...
- SMILESSimplified molecular input line entry specificationThe simplified molecular-input line-entry specification or SMILES is a specification in form of a line notation for describing the structure of chemical molecules using short ASCII strings...
- UN numberUN numberUN numbers or UN IDs are four-digit numbers that identify hazardous substances, and articles in the framework of international transport....
External links
- CAS registry description, by the Chemical Abstracts Service
To find the CAS number of a compound given its name, formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
or structure, the following free resources can be used:
- Chemical Synthesis Database
- PubChem
- ChemSpider
- NLM,NIH ChemIDplus
- NIST Chemistry WebBook
- R&D Chemicals
- NCI Database Browser
- NCI/CADD Chemical Identifier Resolver
- Chemfinder
- ChemSub Online (Multilingual chemical names)
- European chemical Substances Information System (ESIS) - useful for finding EC#EC-NoThe European Commission number, or EC number, also known as EC-No and EC#, is the seven-digit code that is assigned to chemical substances that are commercially available within the European Union...
- NIOSH Pocket Guide to Chemical Hazards, index of CAS numbers