Defects chemical, stereochemical

The evidence for the various types of defect structures is (it is hardly necessary to repeat) provided by X-ray diffraction patterns. The unit cell dimensions, the chemical analysis, and the density settle the composition of the unit cell, and the intensities of the reflections settle the positions of the atoms. Those who studied these structures were forced to the rather surprising conclusions by this evidence. The moral of this tale is that the implications of X-ray diffraction patterns (in conjunction with reliable chemical analyses and densities) should be accepted boldly, even if they conflict with geometrical ideals (the application of the theory of space-groups) or with stereochemical preconceptions. Only in this way is new knowledge and a deeper comprehension of the crystalline state attained. 

It is obvious that, because of intramolecular interactions, the introduction of some kind of chemical and/or stereochemical defects forces also the introduction of conformational defects. 

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