Item _chem_comp.formula

Description

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

               1. Only recognised 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 element symbol and
                  its count, but in general parentheses are not used.

               4. The order of elements depends on whether or not carbon is
                  present. 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