X-ray diffraction from disordered cylindrical lattices

Structure of bis[cyanatobis(di-2-pyridylamine)copper(II)] sulfate bis(di-2-pyridylamine) monohydrate

“…These distortions together suggest the stereochemistry of the CuN4N' chromophore of (I) is best described as trigonally distorted square-based pyramidal, rather than distorted trigonal bipyramidal (Harrison et al, 1981). There are no unusual bond lengths or bond angles in the coordination of the dpyam ligands (Ray & Hathaway, 1978). The individual pyridine rings of the coordinated dpyam ligands are reasonably planar (Ray & Hathaway, 1978), with r.m.s, deviations < 0.025 A.…”

Diffracted intensities from curved crystallites with layer shift. General case

“…Wilson's approach to the case of curved crystallites can be extended and intensity expressions for the above cases readily worked out. However, it was considered necessary to derive a general expression for the diffracted intensities from disordered curved crystallites with layer shift in order to discuss the effect on the intensity as the shift changes gradually.The present calculation is based on the same model of a disordered curved crystallite and all the symbols carry the same meaning as described in the previous work (Ray, De & Bhattacherjee, 1978;De, Ray & Bhattacherjee, 1979). Here, also, R m and W m are taken to be the probabilities of the ruth layer being in the right and wrong places, respectively.…”

“…Substitution of different values of K in (2) leads to the intensity expressions for different cases of layer shift. For K = 2 and 3, it reduces to equation (2) of Ray, De & Bhattacherjee (1978) and equation (2) of De, Ray & Bhattacherjee (1979) corresponding to the ~0/2 and tp/3 shifts, respectively. Based on this general expression, numerical computations have been carried out for intensities with different values of K corresponding to different values of unit angular shifts.…”

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AbstractA general expression for the diffracted intensities from an aggregate of cylindrically curved crystallites with rotational shifts of layers by different amounts has been worked out using a model and treatments similar to those of previous work [Ray, De & Bhattacherjee (1978). Acta Cryst.

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“…A34, 637-638]. Numerical computations for several cases of layer shift showed that the heights of the diffraction peaks decrease accompanying slight changes in peak positions as the unit of angular shift decreases.In two successive publications (Ray, De & Bhattacherjee, 1978;De, Ray & Bhattacherjee, 1979), the authors derived expressions for the diffracted intensities of X-rays from disordered curved crystallites following the model and treatments similar to those adopted by Mitra & Bhattacherjee (1971). One of the disorders considered was characterized by shifts of coaxial cylindrical layers.…”