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Encyclopedia > CAS registry number

CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. They are also referred to as CAS numbers, CAS RNs or CAS #s. A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... A polymer is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. ... An alloy is a homogeneous mixture of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ...


Chemical Abstracts Service (CAS), a division of the American Chemical Society, assigns these identifiers to every chemical that has been described in the literature. The intention is to make database searches more convenient, as chemicals often have many names. Almost all molecule databases today allow searching by CAS number. Chemical Abstracts Service (CAS) is a division of the American Chemical Society, and produces Chemical Abstracts, and related products. ... The American Chemical Society (ACS) is a learned society (professional association) based in the United States that supports scientific inquiry in the field of chemistry. ...


As of June 2007, there were 31,745,275 organic and inorganic substances and 59,039,087 sequences in the CAS registry.[1] Around 50,000 new numbers are added each week. June 2007 is the sixth month of that year. ...


CAS also maintains and sells a database of these chemicals, known as the CAS registry.

Contents

Format

A CAS registry number is separated by hyphens into three parts, the first consisting of up to 6 digits, the second consisting of two digits, and the third consisting of a single digit serving as a check digit. The numbers are assigned in increasing order and do not have any inherent meaning. The checksum is calculated by taking the last digit times 1, the next digit times 2, the next 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 is calculated as (8×1 + 1×2 + 2×3 + 3×4 + 7×5 + 7×6) = 105; 105 mod 10 = 5. A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. ... Modular arithmetic (sometimes called modulo arithmetic, or clock arithmetic because of its use in the 24-hour clock system) is a system of arithmetic for integers, where numbers wrap around after they reach a certain value — the modulus. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...


Isomers, enzymes, and mixtures

Different stereoisomers of a molecule receive different CAS numbers: D-glucose 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 alcohol dehydrogenases has 9031-72-5. An example of a mixture with a CAS number is mustard oil (8007-40-7). Stereoisomerism is the arrangement of atoms in molecules whose connectivity remains the same but their arrangement in space is different in each isomer. ... Glucose (Glc), a monosaccharide (or simple sugar), is the most important carbohydrate in biology. ... 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. ... The term mustard oil is used for two different oils that are made from mustard seeds: a fatty vegetable oil resulting from pressing the seeds, an essential oil resulting from grinding the seeds, mixing them with water, and extracting the resulting volatile oil by distillation. ...


Searches

When using CAS numbers for database searches, it is useful to include the numbers of closely related compounds. For instance, to search for information about cocaine (CAS 50-36-2), one should include cocaine hydrochloride (CAS 53-21-4), since that is the most common form of cocaine when used as a drug. Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. ... In chemistry, hydrochlorides are salts resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (mostly amines). ...


Notes

  1. ^ CAS Registry Number and Substance Counts

See also

The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... The terms EC-No and EC# refer to the seven-digit code (sometimes called the EC number) that has been allocated by the Commission of the European Communities for commercially available chemical substances within the European Union. ... The IUPAC International Chemical Identifier (InChI), developed by IUPAC and NIST, is a digital equivalent of the IUPAC name for any particular covalent compound. ... PubChem is a database of chemical molecules. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... UN numbers or UN IDs are four-digit numbers that identify hazardous substances and products (such as explosives and poisonous materials) of commercial importance. ... To meet Wikipedias content policies, the external links section for this article may require cleanup. ...

External links

  • CAS registry description, by the Chemical Abstracts Service

To find the CAS number of a compound given its name, formula or structure, the following free resources can be used: This article or section does not cite any references or sources. ...

For an extended list of resources, see: The terms EC-No and EC# refer to the seven-digit code (sometimes called the EC number) that has been allocated by the Commission of the European Communities for commercially available chemical substances within the European Union. ...

  • Links to external chemical sources

  Results from FactBites:
 
CAS FAQ Page (974 words)
CAS Registry Numbers (often referred to as CAS RNs or CAS Numbers) are unique identifiers for chemical substances.
A CAS Registry Number itself has no inherent chemical significance but provides an unambiguous way to identify a chemical substance or molecular structure when there are many possible systematic, generic, proprietary, or trivial names.
CAS Registry Numbers are used in many other public and private databases as well as chemical inventory listings and, of course, are included in all CAS-produced databases.
CAS registry number - Wikipedia, the free encyclopedia (412 words)
CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys.
A CAS registry number is separated by hyphens into three parts, the first consisting of up to 6 digits, the second consisting of two digits, and the third consisting of a single digit serving as a check digit.
For example, the CAS number of water is 7732-18-5: the checksum is calculated as (8×1 + 1×2 + 2×3 + 3×4 + 7×5 + 7×6) = 105; 105 mod 10 = 5.
  More results at FactBites »

 
 

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