Describes CIF, the data exchange standard of crystallography. Provides: information for scientists who wish to record or use the results of a single-crystal or powder diffraction experiment; the data ontology necessary for designing interoperable computer applications; accompanying software including machine-readable CIF dictionaries, libraries and utility programs.
An essential guide and reference to CIF for programmers, data managers handling crystal-structure information and practising crystallographers.
The threshold, usually based on multiples of u(I), u(F^2^) or u(F), that serves to identify significantly intense reflections, the number of which is given by _reflns_number_gt. These reflections are used in the calculation of _refine_ls_R_factor_gt.Example:
Related item: _reflns_observed_criterion (alternate)