CAS number

the CAS number (English. CAS Registry NUMBER, CAS = C hemical A bstract S ervice) is an international designation name for chemical materials. For each well-known chemical material (also bio sequences, alloys, polymers) a clear CAS number exists. Sum formulas, (verschiedensprachige) trivial names and even IUPAC - names are not clear and can lead to the mistake in particular by Nichtchemiker. For example acetone can be designated also by Dimethylketon or 2-Propanon correctly - the CAS number makes however a clear identification possible. Different isomers one Molecule carry different CAS numbers.

structure

CAS numbers consisting of three numbers, which are separate by two hyphens. The first number can up to sixNumbers contain, the second number of two numbers. The numbers are to be examined with a check total coded - that is the third number - and thus relatively easily for plausibility. They are assigned in ascending order and contain no internal order.In the year 2005 it gives over 25 million CAS numbers, whereby daily about 4,000 new are added.

CAS numbers become since 1965 of the Chemical Abstracts service, one of the American Chemical Society administered institution with seat in Columbus, Ohio, the USAassigned. The use of the CAS Registry data base, in which to each chemical structure with the help of the CAS number one refers, is liable to pay the costs.

examination of CAS numbers

a CAS register number has the following general form:

<math> Z_n \ ldots Z_4 Z_3 - Z_2 Z_1 - R< /math>

whereby <math> R </math> a check digit and <math> Z_1, Z_2, \ ldots, Z_n< /math> a characteristic number sequence represents.

A CAS number is correct, if

< math> \ mod \ left (\ sum_ {i=1} ^n i \ cdot Z_i, 10 \ right) = R </math>

The modulo function defined for whole numbers< math> \ mod (n, m)< /math> is thatRemainder with division of <math> n< /math> through <math> m< /math>.

examples

• Sildenafilcitrat (active substance of Viagra®) - CAS: 171599-83-0
  
• LSD - CAS: 50-37-3
  
• hydrazine - CAS: 302-01-2
  
• water - CAS: to 7732-18-5
  

see also

• Chemical Abstracts service
• UN-number
• EEC number

Web on the left of

• check total of the CAS number
• English. Explanation to the CAS number
• ChemIDplus - largest free data base with CAS numbers
• SMILECAS data base
• internationally Chemical Safety Cards on German