**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 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. However, they serve the dual purposes 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.

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

**Type:** null

**Category:** category_overview

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