Incommensurately modulated structure of ZnSiO(OH)·HO at high pressure.

High-resolution single-crystal X-ray diffraction experiments on ZnSiO(OH)·HO hemimorphite were conducted at high pressure using diamond anvil cells at several different synchrotron facilities (ESRF, Elettra, DESY). Experimental data confirmed the existence of a previously reported phase transition and revealed the exact nature of the incommensurate modulation. We report the incommensurately modulated structure described in the (3+1)D space group Pnn2(0, β, 0)000.

Local Symmetry Deviation from the Average Structure of MnAs Revealed by Pair Distribution Function.

MnAs is an interesting material due to its magnetocaloric properties, which can be utilized in magnetic refrigeration. However, despite major efforts, its magnetic refrigeration performances in the substituted forms could not be improved compared to the parent MnAs phase. Both small and big box modeling of the pair distribution function of MnAs for the local structure description and powder X-ray diffraction for the average structure reveal an inherent local orthorhombic distortion in the hexagonal structure of MnAs.

: reverse Monte Carlo for multiphase systems.

This work introduces a completely rewritten version of the program (version 7), big-box, reverse Monte Carlo modelling software for analysis of total scattering data. The major new feature of is the ability to refine multiple phases simultaneously, which is relevant for many current research areas such as energy materials, catalysis and engineering. Other new features include improved support for molecular potentials and rigid-body refinements, as well as multiple different data sets.

Charge density studies of single and transient (single to double) boron-oxygen bonds in (NH)BO(OH)·2HO.

A HBO ion which makes up the (NH)BO(OH)·2HO crystal structure has two types of boron-oxygen bonds, single B-O bonds and an intermediate between single and double BO bonds. Differences between these two bond types are visible not only because they differ by their lengths but also a topology of electron density distribution differs. This also gives a hint as to how to distinguish between these two bond types.

Understanding the Deactivation Phenomena of Small-Pore Mo/H-SSZ-13 during Methane Dehydroaromatisation.

Small pore zeolites have shown great potential in a number of catalytic reactions. While Mo-containing medium pore zeolites have been widely studied for methane dehydroaromatisation (MDA), the use of small pore supports has drawn limited attention due to the fast deactivation of the catalyst. This work investigates the structure of the small pore Mo/H-SSZ-13 during catalyst preparation and reaction by operando X-ray absorption spectroscopy (XAS), in situ synchrotron powder diffraction (SPD), and electron microscopy; then, the results are compared with the medium pore Mo/H-ZSM-5.

In situ solid-state NMR and XRD studies of the ADOR process and the unusual structure of zeolite IPC-6.

The assembly-disassembly-organization-reassembly (ADOR) mechanism is a recent method for preparing inorganic framework materials and, in particular, zeolites. This flexible approach has enabled the synthesis of isoreticular families of zeolites with unprecedented continuous control over porosity, and the design and preparation of materials that would have been difficult-or even impossible-to obtain using traditional hydrothermal techniques. Applying the ADOR process to a parent zeolite with the UTL framework topology, for example, has led to six previously unknown zeolites (named IPC-n, where n = 2, 4, 6, 7, 9 and 10).

Thermal and Structural Aspects of the Hydride-Conducting Oxyhydride LaLiHO Obtained via a Halide Flux Method.

Oxyhydrides, in which oxide and hydride anions share the same anionic lattice, are relatively rare compounds. LaLiHO belongs to this family. We report the synthesis of LaLiHO by means of an alkali halide flux method, which allows the production of larger quantities of material relative to the usually adopted synthesis routes.

Triclinic crystal structure distortion of multiferroic BiMnO.

The quadruple perovskite BiMnO obtained via high-pressure synthesis was investigated by high-resolution synchrotron X-ray powder diffraction over a temperature range of 10 to 295 K. Careful Rietveld analysis reveals triclinic lattice distortion of BiMnO at 295 K, which increases upon cooling to 10 K. Also hkl-dependent anisotropic Bragg reflection shape was introduced to give a precise description of the diffracted intensities.

Chemical imaging of Fischer-Tropsch catalysts under operating conditions.

Although we often understand empirically what constitutes an active catalyst, there is still much to be understood fundamentally about how catalytic performance is influenced by formulation. Catalysts are often designed to have a microstructure and nanostructure that can influence performance but that is rarely considered when correlating structure with function. Fischer-Tropsch synthesis (FTS) is a well-known and potentially sustainable technology for converting synthetic natural gas ("syngas": CO + H) into functional hydrocarbons, such as sulfur- and aromatic-free fuel and high-value wax products.

Stacking Faults and Polytypes for Layered Double Hydroxides: What Can We Learn from Simulated and Experimental X-ray Powder Diffraction Data?

Layered double hydroxides (LDH) are a broad group of widely studied materials. The layered character of those materials and their high flexibility for accommodating different metals and anions make them technologically interesting. The general formula for the LDH compound is [MM(OH)][A]·mHO, where M is a divalent metal cation which can be substituted by M trivalent cation, and A is a charge compensating anion located between positively charged layers.

A novel polytype - the stacking fault based γ-MoO3 nanobelts.

γ-MoO3 nanobelts prepared by hydrothermal synthesis were studied by synchrotron radiation powder diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction. Their nm dimensions, in particular in two crystallographic directions, have a profound influence on electrochemical properties during cycling as the cathode material in lithium-ion batteries (LIBs). The diffraction analysis shows clearly that the crystal structure for the γ-MoO3 nanobelts differs significantly from that of bulk α-MoO3.