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Item _chem_comp.formula

Description

              The formula for the chemical component. Formulae are written
               according to the following rules:

               (1) Only recognized element symbols may be used.

               (2) Each element symbol is followed by a 'count' number. A count
                  of '1' may be omitted.

               (3) A space or parenthesis must separate each cluster of
                  (element symbol + count), but in general parentheses are
                  not used.

               (4) The order of elements depends on whether carbon is
                  present or not. If carbon is present, the order should be:
                  C, then H, then the other elements in alphabetical order
                  of their symbol. If carbon is not present, the elements
                  are listed purely in alphabetic order of their symbol. This
                  is the 'Hill' system used by Chemical Abstracts.

Category

Item Examples

Example 1:

C18 H19 N7 O8 S

Mandatory Code

Data Type Code

 

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