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Despite the ubiquity of ferrihydrite in natural sediments and its importance as an industrial sorbent, the nanocrystallinity of this iron oxyhydroxide has hampered accurate structure determination by traditional methods that rely on long-range order. We uncovered the atomic arrangement by real-space modeling of the pair distribution function (PDF) derived(More)
The high-pressure behaviour of α-PbF2 has been investigated by angular-dispersive synchrotron X-ray powder diffraction up to 6.55(8) GPa. The fit of a 3-order BirchMurnaghan equation-of-state gave the volume at zero pressure V0=194.14(4) Å 3 and the bulk modulus b0=47.0(6) GPa with the pressure derivative b’=7.9(4). The continuous-symmetry-measure approach(More)
Atoms and molecules <0.9 nm in diameter can be incorporated in the cages formed by hydrogen-bonded water molecules making up the crystalline solid clathrate hydrates. For these materials crystallographic structures generally fall into 3 categories, which are 2 cubic forms and a hexagonal form. A unique clathrate hydrate structure, previously known only(More)
The phase transition, amorphization, and crystallization behaviors of the topological insulator bismuth selenide (Bi2Se3) were discovered by performing in situ high-pressure angle-dispersive x-ray diffraction experiments during an increasing, decreasing, and recycling pressure process. In the compression process, Bi2Se3 transforms from the original(More)
A new type of disordered substitution alloy of Sb and Te at above 15.1 GPa was discovered by performing in situ high-pressure angle-dispersive X-ray diffraction experiments on antimony telluride (Sb(2)Te(3)), a topological insulator and thermoelectric material, at room temperature. In this disordered substitution alloy, Sb(2)Te(3) crystallizes into a(More)
We present a software developed for automated processing of 2D powder diffraction data-sets as for instance acquired with an image plate setup. For structural analysis, such 2D data usually is integrated to 2θ-scan powder diffraction patterns. Our software is capable to automate such integrations including a geometry correction and automated masking of(More)
The compressibility of nanocrystalline gold (n-Au, 20 nm) has been studied by x-ray total scattering using high-energy monochromatic x-rays in the diamond anvil cell under quasi-hydrostatic conditions up to 71 GPa. The bulk modulus, K0, of the n-Au obtained from fitting to a Vinet equation of state is ~196(3) GPa, which is about 17% higher than for the(More)
The high pressure behaviour of 3R-NbS2 has been investigated by angle-dispersive X-ray powder diffraction using diamond anvil cells up to 14 GPa. The compression behaviour of the structure is highly anisotropic. The compressibility perpendicular to the layers is 2.5 times higher than within the layers. A fit of a 3-order BirchMurnaghan equation of state(More)
The high-pressure behaviour of PbS was investigated by angular dispersive X-ray powder diffraction up to pressures of 6.8 GPa. Experiments were accompanied by first principles calculations at the density functional theory level. By combining both methods reliable data for the elastic properties of rock-salt type αand high-pressure β-PbS could be obtained.(More)