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Core CIF Dictionary version 2.3

_geom_[]

Name

'_geom_[]'

Category: category_overview

Data type: null

Examples:

        _geom_special_details
    ;  All esds (except the esd in the dihedral angle between
       two l.s. planes) are estimated using the full covariance
       matrix. The cell esds are taken into account individually
       in the estimation of esds in distances, angles and
       torsion angles; correlations between esds in cell
       parameters are only used when they are defined by crystal
       symmetry. An approximate (isotropic) treatment of cell esds
       is used for estimating esds involving l.s. planes.
    ;

Example 1 - based on data set bagan of Yamane & DiSalvo [(1996). Acta Cryst. C52, 760-761].

Definition

    	
   Data items in the GEOM and related (GEOM_ANGLE,
   GEOM_BOND, GEOM_CONTACT, GEOM_HBOND and GEOM_TORSION)
   categories record details about the molecular and crystal
   geometry, as calculated from the contents of the ATOM,
   CELL, and SYMMETRY data.

   Geometry data are usually redundant, in that they can be
   calculated from other more fundamental quantities in the data
   block. They serve, however, the dual purpose of providing a
   check on the correctness of both sets of data, and of enabling
   the most important geometric data to be identified for
   publication by setting the appropriate publication flag.
 


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