Z'

[Howard Flack]

>         One of the items that was referred back to the DMG concerned the
> definition of Z'.  It was pointed out that we cannot define Z' until we
> have defined the molecule to which it refers.  This drew attention to the
> fact that CIF currently defines many crystallographic items, but very few
> chemical items (properties of atoms, bonds, molecules, complexes etc.)

For example:
 
   Acta Cryst. (2003). C59, o547-o549

> Crystals of the title compound, C16H28N+·Br-, were grown from solution in a
> mixture of acetone and propan-2-ol by slow evaporation. The structure was
> solved in the polar space group P42bc with five moieties in the asymmetric
> unit, namely two benzyltripropylammonium cations in general positions, and
> two Br- anions in special Wyckoff positions (4a2.. and 4b2..) and one in a
> general position.

   No wonder they don't mention Z' !

H.