Powder diffraction is a major component of any condensed matter scientist’s arsenal, providing the investigator a way to directly map the location of atoms inside of a material. The most common diffraction experiments provide insights into the average atomic structure of materials, which can break down when materials have lowered local symmetry, or are disordered. Analysis of the pair distribut...

Diffraction images with continuous rotation symmetry arise from amorphous systems, but also from regular crystals when investigated by powder diffraction. On the theoretical side, pinwheel patterns and their higher dimensional generalisations display such symmetries as well, in spite of being perfectly ordered. We present first steps and results towards a general frame to investigate such syste...

High-resolution atomic pair distribution functions have been obtained using neutron powder diffraction data from La2-xSrxCuO4 over the range of doping 0<or=x<or=0.30 at 10 K. Despite the average structure getting less orthorhombic, we see a broadening of the in-plane Cu-O bond distribution as a function of doping up to optimal doping. Thereafter the peak abruptly sharpens. The peak broadening c...

The crystal structures of triethyl-1,3,5-triazine-2,4,6-tricarboxylate (I), triethyl-1,3,5-benzenetricarboxylate (II) and tris-2-hydroxyethyl isocyanurate (III) have been determined from conventional laboratory X-ray powder diffraction data using the differential evolution structure solution technique. The determination of these structures presented an unexpectedly wide variation in levels of d...

We provide a brief overview of the first techniques for direct, real-time observation of mechanochemical reactions by milling. Whereas mechanisms and kinetics of solid-state reactions induced by temperature or pressure have been extensively investigated, transformations of materials under continuous impact in a milling assembly remain largely unexplored and based on ex situ studies. The recent ...

Kirfel, Will, and Arndt (1979) reported a quenchable new phase of Si02, synthesized in aqueous solution at 4449 kbar and 6100 C, having the space group P21/a and a crystal structure closely related to coesite. However, single-crystal X-ray and TEM studies have revealed that their observations could be the result of (100)-twinning of C2/e coesite. Therefore, a distinct P2da phase probably does n...

Hollow spheres, hollow capsules and solid spheres of carbon were selectively synthesized by Mg-reduction of hexachlorobutadiene at appropriate reaction conditions. X-ray powder diffraction and Raman spectra reveal that the as-prepared materials have a well-ordered structure. A possible formation mechanism has been proposed.

A direct method for determining powder diffraction data at specific depths from angle-dependent diffraction data is described. The method is non-destructive and only traditional data collections, where the angle of incidence is varied, are required. These angle-dependent spectra are transformed to give diffraction data arising from different depths, which may then be exploited using any convent...

The complete elastic tensor of Fe0.94O (wüstite) has been determined to 10 GPa using acoustic interferometry at GHz frequencies inside a diamond-anvil cell. The soft mode (C44) elastic constant of FeO is reduced by 20% over the experimental pressure range. An unusual discontinuity in the pressure derivatives of C11 and C12 at 4.7+/-0.2 GPa corresponds to the pressure at which the onset of a mag...

Two new cyano-bridged Ru-Cu polymers, the one-dimensional chain {[Cu(tnH)2(H2O)2][Ru(CN)6] ·2H2O}∞ (1) (where tn ) 1,3-diaminopropane) and the pseudo-two-dimensional network {[Cu(tnH)2][Ru(CN)6]}∞ (2), have been prepared and fully characterized. Compounds 1 and 2 both crystallize in the same monoclinic space group, P21/n. Complex 1 was characterized by single crystal X-ray analysis, and compoun...