Small molecule structures and their applications rely on good knowledge of their atomic arrangements. However, the crystal structures of these compounds and materials, which are often composed of fine crystalline domains, cannot be determined with single-crystal X-ray diffraction. Three-dimensional electron diffraction (3D ED) is already becoming a reliable method for the structure analysis of submicrometer-sized organic materials.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
April 2024
Traditional X-ray methods are extensively applied to commercial cement samples in order to determine their physical and chemical properties. Powder patterns are routinely used to quantify the composition of these phase mixtures, but structure determination becomes difficult because of reflection overlapping caused by the high number of different crystal structures. The fast-growing 3D electron diffraction technique and its related automated acquisition protocols arise as a potentially very interesting tool for the cement industry, since they enable the fast and systematic acquisition of diffraction data from individual particles.
View Article and Find Full Text PDFStructural characterization is crucial to understanding protein function. Compared with X-ray diffraction methods, electron crystallography can be performed on nanometer-sized crystals and can provide additional information from the resulting Coulomb potential map. Whereas electron crystallography has successfully resolved three-dimensional structures of vitrified protein crystals, its widespread use as a structural biology tool has been limited.
View Article and Find Full Text PDFPreventing bacteria from adhering to material surfaces is an important technical problem and a major cause of infection. One of nature's defense strategies against bacterial colonization is based on the biohalogenation of signal substances that interfere with bacterial communication. Biohalogenation is catalyzed by haloperoxidases, a class of metal-dependent enzymes whose activity can be mimicked by ceria nanoparticles.
View Article and Find Full Text PDFThermal decomposition is a promising route for the synthesis of metal oxide nanoparticles because size and morphology can be tuned by minute control of the reaction variables. We synthesized CoO nanooctahedra with diameters of ∼48 nm and a narrow size distribution. Full control over nanoparticle size and morphology could be obtained by controlling the reaction time, surfactant ratio, and reactant concentrations.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
August 2019
Electron diffraction tomography (EDT) has gained increasing interest, starting with the development of automated electron diffraction tomography (ADT) which enables the collection of three-dimensional electron diffraction data from nano-sized crystals suitable for ab initio structure analysis. A basic description of the ADT method, nowadays recognized as a reliable and established method, as well as its special features and general applicability to different transmission electron microscopes is provided. In addition, the usability of ADT for crystal structure analysis of single nano-sized crystals with and without special crystallographic features, such as twinning, modulations and disorder is demonstrated.
View Article and Find Full Text PDFThis study made use of a recently developed combination of advanced methods to reveal the atomic structure of a disordered nanocrystalline zeolite using exit wave reconstruction, automated diffraction tomography, disorder modelling and diffraction pattern simulation. By applying these methods, it was possible to determine the so far unknown structures of the hydrous layer silicate RUB-6 and the related zeolite-like material RUB-5. The structures of RUB-5 and RUB-6 contain the same dense layer-like building units (LLBUs).
View Article and Find Full Text PDFThe crystal structure of naturally occurring zaccariniite (RhNiAs) has been studied in Transmission Electron Microscopy (TEM) with variable angle Precession Electron Diffraction (PED) techniques. The analysis of the data has yielded tetragonal cell parameters of 3.86, 3.
View Article and Find Full Text PDFControlling the morphology of noble-metal nanoparticles is mandatory to tune specific properties such as catalytic and optical behavior. Heterodimers consisting of two noble metals have been synthesized, so far mostly in aqueous media using selective surfactants or chemical etching strategies. We report a facile synthesis for Au@Pd and Pd@Au heterodimer nanoparticles (NPs) with morphologies ranging from segregated domains (heteroparticles) to core-shell structures by applying a seed-mediated growth process with Au and Pd seed nanoparticles in 1-octadecene (ODE), which is a high-boiling organic solvent.
View Article and Find Full Text PDFCalcium sulfate is one of the most important construction materials. Today it is employed as high-performance compound in medical applications and cement mixtures. We report a synthesis for calcium sulfate nanoparticles with outstanding dispersibility properties in organic solvents without further functionalization.
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