Validation and completion of the model

A crystal structure solution does not end with the development of a plausible model after the model has been built completely, multiple structural and profile parameters should be refined to achieve the best 

Coelho, Whole-profile structure solution from powder diffraction data using simulated annealing, J. Appl. Cryst. 33, 899 (2000). 

Giacovazzo, Direct methods and powder data state of the art and perspectives, Acta Cryst. A52, 331 (1996). 

Especially when powder data are complex, it may be necessary to use Rietveld technique to re-determine individual intensities before all structural details can be established using Fourier or differential Fourier maps. 

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