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Symmetry dictionary (symCIF) version 1.0.1




   _space_group.name_H-M_alt allows for an alternative
   Hermann-Mauguin symbol to be given. The way in which this
   item is used is determined by the user and should be described
   in the item _space_group.name_H-M_alt_description.  It may,
   for example, be used to give one of the extended Hermann-Mauguin
   symbols given in Table of International Tables for
   Crystallography Volume A (2002) or a full Hermann-Mauguin
   symbol for an unconventional setting.

   Each component of the space-group name is separated by a
   space or an underscore character. The use of a space is
   strongly recommended.  The underscore is only retained
   because it was used in older CIFs. It should
   not be used in new CIFs.

   Subscripts should appear without special symbols. Bars
   should be given as negative signs before the numbers to
   which they apply. The commonly used Hermann-Mauguin symbol
   determines the space-group type uniquely, but a given
   space-group type may be described by more than one
   Hermann-Mauguin symbol. The space-group type is best
   described using  _space_group.IT_number or
   _space_group.name_Schoenflies. The Hermann-Mauguin symbol
   may contain information on the choice of basis but does not
   contain information on the choice of origin. To define the
   setting uniquely, use _space_group.name_Hall, list the
   symmetry operations or generators, or give the transformation
   that relates the setting to the reference setting defined in
   this dictionary under _space_group.reference_setting.

   Ref: International Tables for Crystallography (2002). Volume A,
        Space-group symmetry, edited by Th. Hahn, 5th ed.
        Dordrecht: Kluwer Academic Publishers.


;     loop_
      'C m c m(b n n)'        'Extended Hermann-Mauguin symbol'
      'C 2/c 2/m 21/m'
                   'Full unconventional Hermann-Mauguin symbol'
      'A m a m'
         'Hermann-Mauguin symbol corresponding to setting used'
Three examples for space group No. 63.

Type: char

Mandatory item: no

_symmetry_space_group_name_H-M (cif_core.dic version 1.0)

Related items: _space_group.name_H-M_ref (alternate)
_space_group.name_H-M_full (alternate)

Category: space_group