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.
Residual factor R(Fsqd), calculated on the squared amplitudes of the observed and calculated structure factors, for significantly intense reflections (satisfying _reflns_threshold_expression) and included in the refinement. The reflections also satisfy the resolution limits established by _refine_ls_d_res_high and _refine_ls_d_res_low. sum | F(obs)^2^ - F(calc)^2^ | R(Fsqd) = ------------------------------- sum F(obs)^2^ F(obs)^2^ = squares of the observed structure-factor amplitudes F(calc)^2^ = squares of the calculated structure-factor amplitudes and the sum is taken over the specified reflections