The effect of second coordination sphere interactions on the magnetic anisotropy of transition metals.

In the study of mononuclear transition metal single molecule magnets (SMMs), extensive research has concentrated on identifying optimal coordination geometries around the central metal ion to enhance SMM properties. However, the role of non-covalent interactions in the second coordination sphere has been relatively underexplored. Here, we study the impact of non-covalent Cl⋯H interactions on the magnetic anisotropy of the central Co(II) ion in the distorted axially compressed octahedral complex CoCl(tu) (1) (tu = SC(NH)).

Synthesis and characterization of an organic-inorganic hybrid crystal: 2[Co(en)](VO)·4HO.

Organic-inorganic hybrid crystals have diverse functionalities, for example in energy storage and luminescence, due to their versatile structures. The synthesis and structural characterization of a new cobalt-vanadium-containing compound, 2[Co(en)](VO)·4HO (1) is presented. The crystal structure of 1, consisting of [Co(en)] complexes and chains of corner-sharing (VO) tetrahedra, was solved by single-crystal X-ray diffraction in the centrosymmetric space group P1.

Formation Mechanism and Hydrothermal Synthesis of Highly Active IrRuO Nanoparticles for the Oxygen Evolution Reaction.

Iridium dioxide (IrO), ruthenium dioxide (RuO), and their solid solutions (IrRuO) are very active electrocatalysts for the oxygen evolution reaction (OER). Efficient and facile synthesis of nanosized crystallites of these materials is of high significance for electrocatalytic applications for converting green energy to fuels (power-to-X). Here, we use X-ray scattering to examine reaction conditions for different Ir and Ru precursors resulting in the development of a simple hydrothermal synthesis route using IrCl and KRuO to obtain homogeneous phase-pure IrRuO nanocrystals.

Continuous-Flow Synthesis of ZnMnS Nanoparticles at Ambient Conditions.

With its large direct band gap and good chemical stability, ZnS is suitable for many applications, including light-emitting diodes, panel displays, and photodetection. Here, nanoparticles of ZnS are synthesized phase pure under ambient conditions by precipitation in a simple and scalable continuous-flow reactor. Furthermore, different degrees of Zn substitution with Mn have been investigated, ZnMnS, with = 0.

Exploration of anion effects in solvothermal synthesis using X-ray diffraction.

Solvothermal synthesis presents a facile and highly flexible approach to chemical processing and it is widely used for preparation of micro- and nanosized inorganic materials. The large number of synthesis parameters in combination with the richness of inorganic chemistry means that it is difficult to predict or design synthesis outcomes, and it is demanding to uncover the effect of different parameters due to the sealed and complex nature of solvothermal reactors along with the time demands related to reactor cleaning, sample purification, and characterization. This study explores the effect on formation of crystalline products of six common anions in solvothermal treatment of aqueous and ethanolic precursors.

Stabilizing tetragonal ZrO nanocrystallites in solvothermal synthesis.

Phase-pure tetragonal ZrO nanoparticles have been prepared under simple solvothermal synthesis conditions using different types of alcohols as solvents and studied using X-ray scattering. The variation of tetragonal/monoclinic phase ratios within the produced powders was directly correlated with the amount of generated water from solvent dehydration during the syntheses. By controlling the dehydration kinetics, either choosing primary alcohols of varying thermal stability or by changing synthesis temperatures, it is possible to selectively tune this tetragonal/monoclinic phase ratio.

Refining short-range order parameters from the three-dimensional diffuse scattering in single-crystal electron diffraction data.

Our study compares short-range order parameters refined from the diffuse scattering in single-crystal X-ray and single-crystal electron diffraction data. NbCoSb was chosen as a reference material. The correlations between neighbouring vacancies and the displacements of Sb and Co atoms were refined from the diffuse scattering using a Monte Carlo refinement in DISCUS.

Unveiling the formation mechanism of PbPd intermetallic phases in solvothermal synthesis using X-ray total scattering.

Pd possesses attractive catalytic properties and nano-structuring is an obvious way to enhance catalytic activity. Alloying Pd with Pb has been shown to enhance the catalytic effect of alcohol oxidation. Further optimization of the catalytic effect can be accomplished by controlling the particle size and key to this is understanding the formation mechanism.

The Ambiguous Origin of Thermochromism in Molecular Crystals of Dichalcogenides: Chalcogen Bonds versus Dynamic Se-Se/Te-Te Bonds.

We report thermochromism in crystals of diphenyl diselenide (dpdSe) and diphenyl ditelluride (dpdTe), which is at variance with the commonly known mechanisms of thermochromism in molecular crystals. Variable temperature neutron diffraction studies indicated no conformational change, tautomerization or phase transition between 100 K and 295 K. High-pressure crystallography studies indicated no associated piezochromism in dpdSe and dpdTe crystals.

Benchmark Crystal Structure of Defect-Free Spinel ZnFeO.

Accurate structural models are of paramount importance for elucidating structure-property relationships in functional materials. Spinels (ABO) form a highly important family of materials with complex crystal structures, and subtle structural details have a critical bearing on understanding their physical properties. In some spinels, the space group symmetry is debated, and in general, point defects such as cation inversion and interstitials add complexity.

Pair Distribution Function from Liquid Jet Nanoparticle Suspension using Femtosecond X-ray Pulses.

X-ray scattering data measured on femtosecond timescales at the SACLA X-ray Free Electron Laser (XFEL) facility on a suspension of HfO nanoparticles in a liquid jet were used for pair distribution function (PDF) analysis. Despite a non-optimal experimental setup resulting in a modest Q of ~8 Å , a promising PDF was obtained. The main features were reproduced when comparing the XFEL PDF to a PDF obtained from data measured at the PETRA III synchrotron light source.

Comparative study of conventional and synchrotron X-ray electron densities on molecular crystals.

Five different electron density datasets obtained from conventional and synchrotron single crystal X-ray diffraction experiments are compared. The general aim of the study is to investigate the quality of data for electron density analysis from current state-of-the-art conventional sources, and to see how the data perform in comparison with high-quality synchrotron data. A molecular crystal of melamine was selected as the test compound due to its ability to form excellent single crystals, the light atom content, and an advantageous suitability factor of 3.

A reactor for time-resolved X-ray studies of nucleation and growth during solvothermal synthesis.

Understanding the nucleation and growth mechanisms of nanocrystals under hydro- and solvothermal conditions is key to tailoring functional nanomaterials. High-energy and high-flux synchrotron radiation is ideal for characterization by powder X-ray diffraction and X-ray total scattering in real time. Different versions of batch-type cell reactors have been employed in this work, exploiting the robustness of polyimide-coated fused quartz tubes with an inner diameter of 0.

X-ray diffraction study of the solvothermal formation mechanism of gallium oxide nanoparticles.

Gallium oxides are of broad interest due to their wide band gaps and attractive photoelectric properties. Typically, the synthesis of gallium oxide nanoparticles is based on a combination of solvent-based methods and subsequent calcination, but detailed information about solvent based formation processes is lacking, and this limits the tailoring of materials. Here we have examined the formation mechanisms and crystal structure transformations of gallium oxides during solvothermal synthesis using X-ray diffraction.

Dynamic Lone Pair Expression as Chemical Bonding Origin of Giant Phonon Anharmonicity in Thermoelectric InTe.

Loosely bonded ("rattling") atoms with s lone pair electrons are usually associated with strong anharmonicity and unexpectedly low thermal conductivity, yet their detailed correlation remains largely unknown. Here we resolve this correlation in thermoelectric InTe by combining chemical bonding analysis, inelastic X-ray and neutron scattering, and first principles phonon calculations. We successfully probe soft low-lying transverse phonons dominated by large In z-axis motions, and their giant anharmonicity.

A Machine-Learning-Based Approach for Solving Atomic Structures of Nanomaterials Combining Pair Distribution Functions with Density Functional Theory.

Determination of crystal structures of nanocrystalline or amorphous compounds is a great challenge in solid-state chemistry and physics. Pair distribution function (PDF) analysis of X-ray or neutron total scattering data has proven to be a key element in tackling this challenge. However, in most cases, a reliable structural motif is needed as a starting configuration for structure refinements.

Towards pump-probe single-crystal XFEL refinements for small-unit-cell systems.

Serial femtosecond crystallography for small-unit-cell systems has so far seen very limited application despite obvious scientific possibilities. This is because reliable data reduction has not been available for these challenging systems. In particular, important intensity corrections such as the partiality correction critically rely on accurate determination of the crystal orientation, which is complicated by the low number of diffraction spots for small-unit-cell crystals.

Zr solution structures from pair distribution function analysis.

The structures of metal ions in solution constitute essential information for obtaining chemical insight spanning from catalytic reaction mechanisms to formation of functional nanomaterials. Here, we explore Zr solution structures using X-ray pair distribution function (PDF) analysis across pH (0-14), concentrations (0.1-1.

Direct Visualization of Magnetic Correlations in Frustrated Spinel ZnFe O.

Magnetic materials with the spinel structure (A B O ) form the core of numerous magnetic devices, and ZnFe O constitutes a peculiar example where the nature of the magnetism is still unresolved. Susceptibility measurements revealed a cusp around T  = 13 K resembling an antiferromagnetic transition, despite the positive Curie-Weiss temperature determined to be Θ  = 102.8(1) K.

Synthesis of GeSn nanoparticles under non-inert conditions.

GeSn nanoparticles are interesting for a variety of different optoelectronic devices, however, the synthesis normally involves highly inert conditions, making it less available and promising for future industry implementation. Here, a new non-inert synthesis route is presented which involves preparation of the synthesis under ambient conditions followed by a reaction in autoclaves at temperatures between 400 °C and 500 °C and pressures between 52 bar and 290 bar. The product formation is also investigated with powder X-ray diffraction (PXRD) to study the effect of the reaction parameters in more detail, showing that the Sn-precursor catalyzes the reaction.

On single-crystal total scattering data reduction and correction protocols for analysis in direct space. Corrigendum.

The name of the third author of the article by Koch et al. [Acta Cryst. (2021).

Composition space of PtIrPdRhRu high entropy alloy nanoparticles synthesized by solvothermal reactions.

High entropy alloy (HEA) nanoparticles hold promise in heterogeneous catalysis, and recently, simple and benign solvothermal synthesis was achieved for the equimolar PtIrPdRhRu. Here we experimentally explore the available composition space in this system, and we find that single-phase products can be obtained at significant deviations from the equimolar case.

Scrutinizing particle size related bond strengthening in anatase TiO.

A series of small, middle, and large anatase TiO particles were synthesized through the hydrolysis of titanium tetraisopropoxide (TTIP) to investigate the size-related chemical bond length and strength variation. Unit cell volume contraction with decreasing particle size is identified from Rietveld refinement of high-resolution synchrotron powder X-ray diffraction (PXRD) patterns. More titanium vacancies are also found for smaller anatase particles.

Epitaxial intergrowths and local oxide relaxations in natural bixbyite Fe Mn O.

The scattering pattern of a crystal obeys the symmetry of the crystal structure through the corresponding Laue group. This is usually also true for the diffuse scattering, containing information about disorder, but here a case is reported where the diffuse scattering is of lower symmetry than the parent crystal structure. The mineral bixbyite has been studied by X-ray and neutron scattering techniques since 1928 with some of the most recent studies characterizing the low-temperature transition to a magnetically disordered spin-glass state.

Insight into the Strategies for Improving the Thermal Stability of Efficient N-Type MgSb-Based Thermoelectric Materials.

N-type Mg(Sb,Bi) compounds have recently been demonstrated as promising low-cost efficient thermoelectric materials in low and intermediate temperature ranges; however, the thermal stability of this type of material still poses a great challenge for practical applications. In this work, we conduct a systematic investigation of the thermal stability of several high-performing n-type Mg(Sb,Bi)-based thermoelectric materials in both bulk and powdered forms using X-ray and neutron diffraction. It is found that the bulk sample exhibits a much slower degradation rate based on the evolution of the secondary Bi/Sb phase in comparison with the powdered sample, revealing a clear kinetic effect.