Index

Protein Data Bank exchange dictionary (pdbx) version 1.0521

_pdbx_reflns_twin.type

Definition:

   
  There are two types of twinning: merohedral or hemihedral 
                               non-merohedral or epitaxial

  For merohedral twinning the diffraction patterns from the different domains are
  completely superimposable.   Hemihedral twinning is a special case of merohedral 
  twinning. It only involves two distinct domains.
 
  In the case of non-merohedral or epitaxial twinning  the reciprocal 
  lattices do not superimpose exactly. In this case the  diffraction pattern 
  consists of two (or more) interpenetrating lattices, which can in principle 
  be separated.

Type: line

Mandatory item: yes

Category: pdbx_reflns_twin