The Best Representative of Each Unique Polymorph in the CSD
It is the policy of the Cambridge Crystallographic Data Centre to aim for as
complete as possible coverage of the literature, which means that multiple
determinations of the same crystal structure are all included. As these
multiple inclusions could introduce bias in statistical surveys, a procedure
has been developed to
eliminate these duplicate crystal structures. The details are described in the
paper:
Searching the Cambridge Structural Database for the 'Best' Representative
of Each Unique Polymorph.
J. van de Streek, Acta Cryst., B62, 567-579, 2006
[DOI:10.1107/S0108768106019677]
The four lists of CSD reference codes (refcodes) of unique polymorphs are provided as
supplementary data for this paper. A zip file containing all four lists as
published for version 5.27, 2006 release of the CSD can be downloaded (2.8 MB):
These lists have been updated for version 5.30, 2009 release of the CSD.
Text (.txt) versions can be downloaded here (2.4 MB each):
A zip file containing all four lists for version 5.30 can be downloaded here (3.4 MB):
The four files contain lists of refcodes that can be used as filters in ConQuest
or Mercury. After downloading, the extensions of the four files must be changed
from .txt to .gcd. Please note that these files are
only useful for CSD System subscribers.
As a free service, CCDC may be unable to provide support for the above files.
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