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General CIF Terminology

Given in the following table are the general terms referred to in the CIF, and on the following page are some illustrative examples.

CIF terminology:

text stringa string of characters delimited by blank spaces, quotes, or semi-colons with one of the forementioned characters as the first character on a line
e.g. 'A New Sodium Chloride Structure'
data namea text string preceded by an underline character
e.g. _chemical_formula_weight
data itema text string not starting with an underline, but preceded by a data name
e.g. _data_name green
data loopa list of data names, preceded by loop_ and followed by a repeated list of data items
data blocka collection of data names and data items (which can be in loops) preceded by a data_code statement (where code is a name input by the user) and terminated by a different data_code statement for a new data block or the end of the file.
data filea collection of data blocks

All the data names used in a CIF, and the following examples, are largely self-explanatory. For example, _cell_length_a denotes the length of the unit cell parameter a. More detailed explanations of specific data names can be found in the CIF dictionary found in the links given at the end of this section.

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© Copyright 1997-2006.  Birkbeck College, University of London. Author(s): Martin Attfield