CAS Number (CAS Registry Number or called CAS Number, CAS Rn, CAS #), also known as CAS Registry Number, is a substance (compound, polymer materials, biological sequence (Biological sequences), mixture or alloy) of the unique number identification number.

Organization under the American Chemical Society Chemical Abstracts Service (Chemical Abstracts Service, CAS) is responsible for each substance appeared in the literature assigned a CAS number, its purpose is to avoid a variety of chemical names of trouble, the database the search is more convenient. Today, almost all chemical databases allow CAS number search.

To December 25, 2005, CAS has registered 27,655,947 substances latest data, and also to the more than 4,000 daily rate of increase.

American Chemical Abstracts Service - developed for the chemical substance registration number

Chemical aspects:

CAS Registry Number or called CAS Number, also known as CAS Registry Number

American Chemical Abstracts Service (Chemical Abstracts Service, CAS) for the chemical substance formulated registration number, the number has more than one name is retrieved information on chemical substances important tool. Is a substance (compounds, polymers, biological sequences (Biological sequences), mixture or alloy of eight unique digital identification number.

Under the American Chemical Society CAS and are responsible for each of the material appeared in the literature assigned a CAS number, its purpose is to avoid chemical substances troubles many names, the database search is more convenient. Today, almost all chemical databases allow CAS number search. To December 25, 2005, CAS has registered 27,115,156 substances latest data, and also to the more than 4,000 daily rate of increase.

Format: a CAS number with a hyphen "-" is divided into three parts, the first part of a 2-6 digit, the second part there are two figures, and the third part has a number as a checksum. CAS number in ascending order and no intrinsic meaning. Checksum is calculated as follows: CAS sequence number (first and second part numbers) by multiplying the last 1, the last second multiplied by 2, and so on, and then all of the products are summed, and then and by 10, while the rest is the third part of the checksum. For example, water (H2O) CAS number of the first two parts are 7732-18, its checksum = (8 × 1 +1 × 2 +2 × 3 +3 × 4 +7 × 5 +7 × 6) mod 10 = 105 mod 10 = 5. (Mod is the remainder operator)

Isomers, and mixtures enzymes: different isomeric molecules have different CAS numbers, for example, dextrose (D-glucos) The CAS number is 50-99-7, L-glucose (L-glucose) is 921 -60-8, α D-glucose (α-D-glucose) is 26655-34-5. Occasionally there is a class of molecules with a CAS number, such as a group of alcohol dehydrogenase (Alcohol dehydrogenase) The CAS number is 9031-72-5. Mixture, such as mustard oil (mustard oil) CAS number is 8007-40-7.

In a nutshell is student number of chemical substances.