The Crystallographic Information File (CIF) was adopted in 1990 by the International Union of Crystallography as a file structure for the archiving and distribution of crystallographic information. The CIF standard is now well established and is in regular use for reporting crystal structure determinations to
Acta Crystallographicaand other journals. The structure of CIF is flexible and extensible and is compatible with other evolving standards. It is well suited to relational and object-oriented models, and is being adopted by the crystallographic databases. This paper reviews the development of CIF and describes its salient features. Future extension of the standard to include implementation of methods will allow CIF to exploit the potential of advanced information-handling software.