Comparative refinement of correct and incorrect structural models of tetra­butylammonium tetra­butylborate – pitfalls arising from poor-quality data

Obviously erroneous structural models of tetrabutylammonium tetrabutylborate can have lower values of R and wR than the correct one.

Combined structure-factor phase measurement and theoretical calculations for mapping of chemical bonds in GaN

Extinction-free structure-factor phase and amplitude measurements by convergent-beam electron diffraction in GaN provide a map of the polar bonds.

High-resolution study of dynamical diffraction phenomena accompanying the Renninger (222/113) case of three-beam diffraction in silicon

The effect of the total reflection of the incident beam into the 222 reflected beam in the Renninger (222/113) case in Si was experimentally observed by using a highly monochromatic beam with high angular collimation in both the vertical and horizontal planes.

Multipole electron-density modelling of synchrotron powder diffraction data: the case of diamond

Accurate structure factors to high resolution can be obtained for small-unit-cell inorganic solids from synchrotron powder diffraction data measured in minutes.

Two-wave approximation in surface effects in asymmetric Laue crystals

Surface effects in Laue diffraction of X-rays by crystals are investigated by means of Takagi–Taupin equations.

Non-periodicity in nanoparticles with close-packed structures

It is observed experimentally that nanocrystals from II–VI compounds like CdS have a high density of stacking faults. It is argued that these are not crystal defects but rather represent a characteristic feature for such materials.

Three-beam X-ray rocking curves calculated from computer-simulated pinhole topographs

A method for computing X-ray three-beam rocking curves is described. It is based on fast-Fourier-transforming X-ray amplitudes in pinhole topographs which were computer-simulated based on the Takagi–Taupin equation.

Structure factor for decorated Penrose tiling in physical space

Using a statistical approach, the structure factor for an arbitrarily decorated Penrose tiling was derived in physical space and used for the structure refinement of decagonal quasicrystals.

Interbranch transient beating of X-ray intensities in deformed crystals

An appreciable beating of the X-ray intensities may be induced by a lattice distortion that produces interbranch transformations of the local dispersion surface. In X-ray plane-wave topography, this effect may be observed as interference fringes arising around the kinematical image of a defect.