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Cedrol‐like compounds are of pharmacological interest due to their diverse range of medicinal effects and are used globally in traditional medicines and cosmetics. Many cedrol tautomers are known from molecular studies but few have been studied in crystalline form by X‐ray diffraction. Acicular white crystals collected from the wood of eastern red cedar (Juniperus virginiana) are determined to be (+)‐cedrol hemihydrate, namely, (1S,2R,5S,7R,8R)‐2,6,6,8‐tetramethyltricyclo[5.3.1.01,5]undecan‐8‐ol hemihydrate, C15H26O·0.5H2O, a novel packing of two unique cedrol molecules (Z′ = 2) with a single water molecule [space group P212121; a = 6.1956 (1), b = 14.5363 (1), and c = 30.9294 (4) Å]. The hydrogen bonding forms a one‐dimensional spiral chain running along the a axis, following the chirality of the cedrol molecule, through hydrogen‐bonding interactions with a right‐handed helical configuration in graph‐set notation Δ‐C33(6) > a > c > b. The crystal packing and symmetry are different from crystalline isocedrol due to the different hydrogen‐bonding geometry. [ABSTRACT FROM AUTHOR]

Neutron scattering is a powerful but expensive technique to study materials and discover new matter. Advanced detector technology has significantly improved the efficiency of neutron experiments, increasing the complexity of neutron data reduction and analysis. Machine learning (ML) brings new directions for neutron diffraction data reduction and experiment operation. This work presents an ML‐assisted data reduction and analysis method for precise recognition of Bragg peaks and the corresponding regions of interest; it can then automatically screen and align a measured crystal using the recognized peaks, and subsequently plan and optimize the data collection with user‐provided information and uncertainty quantification values of detected peaks. This method shows robust performance in different complex sample environments and enables automated single‐crystal neutron diffraction. [ABSTRACT FROM AUTHOR]

The effects of composition on the phase formation of multicomponent garnet crystals grown via directional solidification by the micro-pulling-down method are studied. A relatively wide range of rare-earth (RE) average ionic radii (AIR) is explored by formulating ten compositions from the system (Lu,Y,Ho,Dy,Tb,Gd)3Al5O12. Crystals were grown at either 0.05 or 0.20 mm min-1. The hypothesis is that multicomponent compounds with large AIR will form secondary phases as the single-RE aluminum garnets formed by larger Tb3+ or Gd3+; this will result in crystals of poor optical quality. Crystals with large AIR have a central opaque region in optical microscopy images, which is responsible for their reduced transparency compared to crystals with small AIR. Slow pulling rates suppress the formation of the opaque region in crystals with intermediate AIR. Powder and single-crystal X-ray diffraction and electron probe microanalysis results indicate that the opaque region is a perovskite phase. Scanning electron microscopy and energy dispersive spectroscopy measurements reveal eutectic inclusions at the outer surface of the crystals. The concentration of the eutectic inclusions increases with increasing AIR. [ABSTRACT FROM AUTHOR]

A user‐friendly program has been developed to analyze diffuse scattering from single crystals with the reverse Monte Carlo method. The approach allows for refinement of correlated disorder from atomistic supercells with magnetic or structural (occupational and/or displacive) disorder. The program is written in Python and optimized for performance and efficiency. Refinements of two user cases obtained with legacy neutron‐scattering data demonstrate the effectiveness of the approach and the developed program. It is shown with bixbyite, a naturally occurring magnetic mineral, that the calculated three‐dimensional spin‐pair correlations are resolved with finer real‐space resolution compared with the pair distribution function calculated directly from the reciprocal‐space pattern. With the triangular lattice Ba3Co2O6(CO3)0.7, refinements of occupational and displacive disorder are combined to extract the one‐dimensional intra‐chain correlations of carbonate molecules that move toward neighboring vacant sites to accommodate strain induced by electrostatic interactions. The program is packaged with a graphical user interface and extensible to serve the needs of single‐crystal diffractometer instruments that collect diffuse‐scattering data. [ABSTRACT FROM AUTHOR]

In this study we quantified the percent CaCO3 polymorph composition in otoliths of larval and juvenile Lake Sturgeon Acipenser fulvescens via X‐ray microdiffraction. Sagittal otoliths of sub‐adults were primarily composed of aragonite (> 90%) while the lapilli otoliths were 100% vaterite. This is the first time the presence of aragonite in otoliths has been reported in an acipenseriform and is surprising given that the ability to form aragonite otoliths was not thought to have evolved until the separation of teleost and holostean species from other Actinopterygian fishes (e.g., sturgeon, paddlefish, gar). [ABSTRACT FROM AUTHOR]

Neutron diffraction and spectroscopy offer unique insight into structures and properties of solids and molecular materials. All neutron instruments located at the various neutron sources are distinct, even if their designs are based on similar principles, and thus, they are usually less familiar to the community than commercial X‐ray diffractometers and optical spectrometers. Major neutron instruments in the USA, which are open to scientists around the world, and examples of their use in coordination chemistry research are presented here, along with a list of similar instruments at main neutron facilities in other countries. The reader may easily and quickly find from this minireview an appropriate neutron instrument for research. The instruments include single‐crystal and powder diffractometers to determine structures, inelastic neutron scattering (INS) spectrometers to probe magnetic and vibrational excitations, and quasielastic neutron scattering (QENS) spectrometers to study molecular dynamics such as methyl rotation on ligands. Key and unique features of the diffraction and neutron spectroscopy that are relevant to inorganic chemistry are reviewed. Major instruments in the USA for (1) single‐crystal and powder neutron diffraction and (2) inelastic neutron scattering (INS) and quasielastic neutron scattering (QENS) spectroscopy are presented with examples of their use in coordination chemistry. Similar instruments at main neutron facilities in other countries are listed for the reader to find a suitable neutron instrument for research. [ABSTRACT FROM AUTHOR]

Neutron diffraction from aligned stacks of lipid bilayers is examined using the Wide‐Angle Neutron Diffractometer (WAND), located at the High Flux Isotope Reactor, Oak Ridge, Tennessee, USA. Data were collected at different levels of hydration and neutron contrast by varying the relative humidity (RH) and H2O/D2O ratio from multi‐bilayers of dioleoylphosphatidylcholine and sunflower phosphatidylcholine extract aligned on single‐crystal silicon substrates. This work highlights the capabilites of a newly fabricated sample hydration cell, which allows the lipid bilayers to be hydrated with varying H/D ratios from the RH generated by saturated salt solutions, and also demonstrates WAND's capability as an instrument suitable for the study of aligned lipid multi‐bilayers. [ABSTRACT FROM AUTHOR]

The first high-resolution neutron protein structure of perdeuterated rubredoxin from Pyrococcus furiosus ( PfRd) determined using the new IMAGINE macromolecular neutron crystallography instrument at the Oak Ridge National Laboratory is reported. Neutron diffraction data extending to 1.65 Å resolution were collected from a relatively small 0.7 mm3 PfRd crystal using 2.5 d (60 h) of beam time. The refined structure contains 371 out of 391, or 95%, of the D atoms of the protein and 58 solvent molecules. The IMAGINE instrument is designed to provide neutron data at or near atomic resolution (1.5 Å) from crystals with volume <1.0 mm3 and with unit-cell edges <100 Å. Beamline features include novel elliptical focusing mirrors that deliver neutrons into a 2.0 × 3.2 mm focal spot at the sample position with full-width vertical and horizontal divergences of 0.5 and 0.6°, respectively. Variable short- and long-wavelength cutoff optics provide automated exchange between multiple-wavelength configurations (λmin = 2.0, 2.8, 3.3 Å to λmax = 3.0, 4.0, 4.5, ∼20 Å). These optics produce a more than 20-fold increase in the flux density at the sample and should help to enable more routine collection of high-resolution data from submillimetre-cubed crystals. Notably, the crystal used to collect these PfRd data was 5-10 times smaller than those previously reported. [ABSTRACT FROM AUTHOR]

The article describes the four-circle single-crystal neutron diffractometer, HB-3A, which was installed and commissioned on a thermal beamline at the High Flux Isotope Reactor at Oak Ridge National Laboratory in Tennessee. Among the components of the instrument include a multi-wafer neutron monochromator, a goniometer, and a helium detector. The instrument can be used to studies of nuclear and magnetic structures as a function of composition and temperature and to determine hydrogen bonding.

Analyzes the temperature dependence of anisotropic displacement parameters in a filled skutterudite. Structure-property relationships; Neutron diffraction results; Structural parameters from X-ray diffraction.

Single crystals of K3Lu(PO4)2 are prepared from mixtures of Lu2O3 and K4P2O7 (Pt crucible, 1508 K, 4 h). [ABSTRACT FROM AUTHOR]