Accurate charge densities from powder X-ray diffraction

Accurate determination of X-ray energies using powder diffraction

We report synchrotron energy determinations using the powder diffraction patterns of Si (640b) and LaB6 (660) standard reference powders at a number of energies between 5 and 20 keV. The fitted peak positions of all peaks recorded on image plates were used in each energy determination. Several sources of systematic error were investigated and their connection led to physically reasonable and co...

X-Ray Powder Diffraction Metrics

To compare sample data from x-ray diffraction a suitable metric is developed to evaluate the similarity (or dissimilarity) between samples and to compare it to a references. The methodology focuses on the d-lines and uses the intensity measurements indirectly in the algorithm. The resulting d-line distribution and summary statistics of the differences is used to establish whether a true differe...

Two-dimensional X-ray powder diffraction

X-ray powder diffraction on proteins

Macromolecular structures are traditionally determined by means of single crystal X ray diffraction from protein crystals of micrometer dimensions. Nevertheless, the growth of good quality single crystals can be very difficult or even impossible, especially in cases of large proteins, membrane proteins or protein complexes. Modern developments of X-ray powder diffraction have allowed the struct...

Sr–fresnoite determined from synchrotron X-ray powder diffraction data

The fresnoite-type compound Sr2TiO(Si2O7), distrontium oxidotitanium disilicate, has been prepared by high-temperature solid-state synthesis. The results of a Rietveld refinement study, based on high-resolution synchrotron X-ray powder diffraction data, show that the title compound crystallizes in the space group P4bm and adopts the structure of other fresnoite-type mineral samples with general...