Macromolecular dictionary (mmCIF) version 2.0.09

_refine.ls_abs_structure_Flack

Name:
'_refine.ls_abs_structure_Flack'

Definition:

   The measure of absolute structure (enantiomorph or polarity) as
   defined by Flack (1983).

   For centrosymmetric structures, the only permitted value, if the
   data name is present, is 'inapplicable', represented by '.' .

   For noncentrosymmetric structures the value must lie in the
   99.97% Gaussian confidence interval  -3u =< x =< 1 + 3u and a
   standard uncertainty (estimated standard deviation) u must
   be supplied. The item range of [0.0:1.0] is correctly
   interpreted as meaning (0.0 - 3u) =< x =< (1.0 + 3u).

      Ref: Flack, H. D. (1983). Acta Cryst. A39, 876-881.

Type: float

Type conditions: esd

Mandatory item: no

Alias:
_refine_ls_abs_structure_Flack (cif_core.dic version 2.0.1)
The permitted range is [0.0, 1.0]

Related item: _refine.ls_abs_structure_Flack_esd (associated_esd)

Category: refine