The purpose of this conference was to assess the progress that has been made in the theory, techniques, and applications of powder diffraction data since the first highly successful symposium on Accuracy in Powder Diffraction held at NIST (then the National Bureau of Standards) in 1979, as well as to define problem areas where further work is needed. The proceedings of the first symposium, publ...

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...

Figure S1: X-ray powder diffraction pattern of the iron oxide nanospheres sample. X-ray Powder diffraction (XRPD) was measured on a conventional in-house powder diffractometer using Cu Kα radiation. Rietveld refinement yields cubic lattice parameters of 8.362(2) Å for the nanospheres and 8.348(1) Å for the nanocubes, which are both close to the cubic spinel lattice parameter of maghemite. The r...

Pinwheel patterns and their higher dimensional generalisations display continuous circular or spherical symmetries in spite of being perfectly ordered. The same symmetries show up in the corresponding diffraction images. Interestingly, they also arise from amorphous systems, and also from regular crystals when investigated by powder diffraction. We present first steps and results towards a gene...

Electron microscopy techniques yield information for crystal structure analysis that is remarkably complementary to that obtained from X-ray powder diffraction data. Structures of polycrystalline materials that resist solution by either method alone can sometimes be solved by combining the two. For example, the intensities extracted from an X-ray powder diffraction pattern are kinematical and c...

The determination ab initio of crystal structures from powder diffraction data has been one of the major advance of modern powder crystallographyl. It is a consequence of the developments occurred in instrument resolution, powder pattern indexing and fitting techniques, e.g. the problem of peak overlap resulting from the collapse of the three dimensional pattern into one dimensional powder diff...

In the 12 years since the last Accuracy in Powder Diffraction meeting, there have been significant advances. Just an example: a search of the Protein Data Bank for “powder” shows just 2 hits for before 2000, 19 for 2000‐2005, 27 for 2005‐2010 and 31 for 2010‐present. The current Cambridge Crystallographic Data Base (CCDC) shows 2354 molecular crystal structures determined via powder diffraction...

A number of molecular crystal structures of two families of organic compounds pharmaceutically important heterocycles and dyes successfully solved from various powder diffraction data are presented. The obtained results demonstrate the power and reliability of powder diffraction methods in their applications to characterization solid organic materials which can only be prepared in polycrystalli...

The structure solution from powder diffraction has undergone an intense evolution during the last 20 years, but is far from being routine. Current challenges of powder crystallography include ab initio crystal structure determination on real samples of new materials with specific microstructures, characterization of intermediate reaction products from in situ, in operando studies and novel phas...

The International Centre for Diffraction Data (ICDD) is responding to the changing needs in powder diffraction and materials analysis by developing the Powder Diffraction File (PDF) in a very flexible relational database (RDB) format. The PDF now contains 136,895 powder diffraction patterns. In this paper, an attempt is made to give an overview of the PDF-4, search/match methods and the advanta...