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On enantiomorph‐polarity estimation
The behaviour of Rogers's η parameter for enantiomorph-polarity estimation is examined theoretically and experimentally on simulated intensity data for seven well-assorted compounds. An alternative
Use of intensity quotients and differences in absolute structure refinement
Differences and quotients can be defined using Friedel pairs of reflections and applied in refinement to enable absolute structure to be determined precisely even for light atom crystal structures.
Reporting and evaluating absolute-structure and absolute-configuration determinations
Detailed practical and numerical information is provided for undertaking and evaluating absolute-structure and absolute-configuration determinations. The interpretation of numerical values of x, the
The use of the Durbin–Watson d statistic in Rietveld analysis
A weighted form of the Durbin–Watson d statistic [Durbin & Watson (1971). Biometrika, 58, 1–19] has been used to quantify the serial correlation between adjacent least-squares residuals in Rietveld
The mean-square Friedel intensity difference in P1 with a centrosymmetric substructure.
Analysis of analytical expressions confirms that both resonant and non-resonant atoms are necessary to produce differences in intensity between Friedel opposites and shows that in some circumstances atoms may lie on a centrosymmetric substructure without diminishing the Bijvoet intensity ratio.
Electric field gradients and charge density in corundum, α-Al2O3
The charge density in α-Al2O3 has been refined with respect to X-ray structure factors [complete spheres for both Mo Kα and Ag Kα radiations with (sin θ/λ)max = 1.19 and 1.495 A-1 respectively] and
Chiral and Achiral Crystal Structures
An extensive study and analysis of the concepts, classification, presentation, and nomenclature of chirality and lack of chirality in crystal structures and their constituents is presented. Oriented
Louis Pasteur's discovery of molecular chirality and spontaneous resolution in 1848, together with a complete review of his crystallographic and chemical work.
  • H. Flack
  • Chemistry
    Acta crystallographica. Section A, Foundations of…
  • 1 September 2009
All of Pasteur's crystallographic and chemical work is passed in review, a topic very rarely broached, and the term dissymmetry used by Pasteur is discussed.
Applications and properties of the Bijvoet intensity ratio.
It is found that, although the Bijvoet intensity ratio has a strong dependence on sin theta/lambda, extrapolation to sin theTA/lambda = 0 of model intensity pairs leads to values satisfactorily close to those expected.