Crystallographic Information Framework

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Core dictionary (coreCIF) version 2.4.5




   Formula with each discrete bonded residue or ion shown as a
   separate moiety. See the _chemical_formula_[] category 
   description for rules for writing chemical formulae. In addition 
   to the general formulae requirements, the following rules apply:
      (1) Moieties are separated by commas ','.
      (2) The order of elements within a moiety follows general rule
         (5) in the _chemical_formula_[] category description.
      (3) Parentheses are not used within moieties but may surround
         a moiety. Parentheses may not be nested.
      (4) Charges should be placed at the end of the moiety. The
         charge '+' or '-' may be preceded by a numerical multiplier
         and should be separated from the last (element symbol +
         count) by a space. Pre- or post-multipliers may be used for
         individual moieties.


'C7 H4 Cl Hg N O3 S'
'C12 H17 N4 O S 1+, C6 H2 N3 O7 1-'
'C12 H16 N2 O6, 5(H2 O1)'
'(Cd 2+)3, (C6 N6 Cr 3-)2, 2(H2 O)'

Type: char

Category: chemical_formula