4 2024 Mine Water Energy Symposium - British Geological Survey By news.google.com Published On :: Mon, 08 Apr 2024 13:14:44 GMT 2024 Mine Water Energy Symposium British Geological Survey Full Article
4 Will 2024 be the Year of the Aurora? - British Geological Survey By news.google.com Published On :: Fri, 23 Feb 2024 17:56:24 GMT Will 2024 be the Year of the Aurora? British Geological Survey Full Article
4 BGS signs memorandum of understanding with Serviço Geológico do Brasil - British Geological Survey By news.google.com Published On :: Wed, 10 Apr 2024 07:00:00 GMT BGS signs memorandum of understanding with Serviço Geológico do Brasil British Geological Survey Full Article
4 2024 BGS summer placements scheme - British Geological Survey By news.google.com Published On :: Mon, 27 May 2024 16:11:34 GMT 2024 BGS summer placements scheme British Geological Survey Full Article
4 BGS Open Day 2024 - British Geological Survey By news.google.com Published On :: Tue, 27 Feb 2024 14:35:15 GMT BGS Open Day 2024 British Geological Survey Full Article
4 3aH,4H,5H,8H,9H,9aH-Cycloocta[d][1,3]dioxole-2-thione By journals.iucr.org Published On :: The thionocarbonate of trans-cyclooctenediol, C9H12O2S, crystallizes with a 9/1 disorder in the position of the R,R and S,S-enantiomers. As a result of trans-annulation, both rings adopt a twist conformation. Full Article text
4 2-Amino-5-oxo-4-(thiophen-2-yl)-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile By journals.iucr.org Published On :: In the crystal structure of the title compound, intermolecular N—H⋯N and N—H⋯O hydrogen bonds form a two-dimensional supramolecular network along the ac plane, contributing to the cohesion of the crystal. Full Article text
4 Tris(4-chlorophenyl) phosphate By journals.iucr.org Published On :: In the title compound, the symmetric phosphate derived from para-chlorophenol and phosphoric acid, two of the three aromatic moieties adopt syn-orientation towards the P&z-dbnd;O bond while the last chlorophenol ring is pointing away from this bond. In the extended structure, C—H⋯O bonds connect the individual molecules into sheets lying perpendicular to the crystallographic b axis. Full Article text
4 Structural insights into 1,4-bis(neopentyloxy)pillar[5]arene and the pyridine host–guest system By journals.iucr.org Published On :: The crystal structure of a neopentyloxypillar[5]arene with two pyridine molecules encapsulated in the macrocyclic cavity is reported. Full Article text
4 2,4-Dichloro-6-{N-[2-(trifluoromethyl)phenyl]carboximidoyl}phenol By journals.iucr.org Published On :: The title compound was synthesized by the condensation between trifluoromethylaniline and dichlorosalicylaldehyde by nucleophilic addition, forming a hemiaminal, followed by a dehydration to generate an imine. The compound crystallizes in an orthorhombic Pbca (Z = 8) space group with a dihedral angle of 44.70 (5)° between the two aromatic rings. In the crystal, the molecules pack together to form a zigzag pattern along the c axis. Full Article text
4 Ethyl (2RS,3SR,4RS)-1-ethyl-2-(furan-2-yl)-4-hydroxy-5-oxopyrrolidine-3-carboxylate By journals.iucr.org Published On :: The crystal structure of a pyrrolidine analogue obtained from the stereoselective reduction of the enolic form of 4-hydroxy-2-furyl-pyrrolecarboxylate is described. Full Article text
4 From `crystallographic accuracy' to `thermodynamic accuracy': a redetermination of the crystal structure of calcium atorvastatin trihydrate (Lipitor®) By journals.iucr.org Published On :: The crystal structure of calcium atorvastatin trihydrate was redetermined from previously published synchrotron powder diffraction data to give a much-improved agreement with two independent density-functional theory calculations. Full Article text
4 Spin reorientation and the interplay of magnetic sublattices in Er2CuMnMn4O12 By journals.iucr.org Published On :: We show that the interplay of multiple magnetic sublattices in Er2CuMnMn4O12 leads to four magnetic phase transitions characterized by the onset of ferrimagnetic order, spin-reorientation, spin canting, and the polarization of Er ions. While we elucidate numerous features of this complex magnetic system, the exact nature of the low-temperature coupling between erbium and manganese, and the origin of a k = (0, 0, ½) modulation, remain intriguing topics for future studies. Full Article text
4 Atypical phase transition, twinning and ferroelastic domain structure in bis(ethylenediammonium) tetrabromozincate(II) bromide, [NH3(CH2)2NH3]2[ZnBr4]Br2 By journals.iucr.org Published On :: A unique phase transition, twinning and ferroelastic domain structure in [NH3(CH2)2NH3]2[ZnBr4]Br2 is found. The new additional domain structure is observed at the phase transition on heating, which is preserved after cooling to room temperature. Full Article text
4 Structures of hexamethyl-[1,1'-biphenyl]-4,4'-diammonium salts By journals.iucr.org Published On :: The structures of nine hexamethyl-[1,1'-biphenyl]-4,4'-diammonium (HMB) salts are described Full Article text
4 The incommensurate composite YxOs4B4 (x = 1.161) By journals.iucr.org Published On :: Tetragonal YxOs4B4 (x = 1.161) is an incommensurate composite of columns of Y atoms in a three-dimensional Os4B4 framework. The structure was refined using the superspace approach. Full Article text
4 Polymorphism of Pb5(PO4)3OHδ within the LK-99 mixture By journals.iucr.org Published On :: A new orthorhombic crystal Pb5(PO4)3OHδ of space-group symmetry Pnma significantly differs differing from the hexagonal apatite phases of Pb10(PO4)6O and Pb5(PO4)3OH. Full Article text
4 Atypical phase transition, twinning and ferroelastic domain structure in bis(ethylenediammonium) tetrabromozincate(II) bromide, [NH3(CH2)2NH3]2[ZnBr4]Br2 By journals.iucr.org Published On :: 2024-11-04 Single-crystal growth, differential thermal analysis (DTA), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X-ray structural studies and polarized microscopy observations of bis(ethylenediammonium) tetrabromozincate(II) bromide [NH3(CH2)2NH3]2[ZnBr4]Br2 are presented. A reversible phase transition is described. At room temperature, the complex crystallizes in the monoclinic system. In some cases, the single crystals are twinned into two or more large domains of ferroelastic type with domain walls in the (100) crystallographic plane. DTA and DTG measurements show chemical stability of the crystal up to ∼538 K. In the DSC studies, a reversible isostructural phase transition was revealed at ∼526/522 K on heating/cooling run, respectively. Optical observation on the heating run reveals that at the phase transition the plane of twinning (domain wall) does not disappear and additionally the appearance of a new domain structure of ferroelastic type with domain walls in the planes (101), (101), (100) and (001) is observed. The domain structure pattern is preserved after cooling to the room-temperature phase and the symmetry of this phase is unchanged. Full Article text
4 The incommensurate composite YxOs4B4 (x = 1.161) By journals.iucr.org Published On :: 2024-10-31 YxOs4B4 (x = 1.161) crystallizes as a tetragonal incommensurate composite of columns of Y atoms extending along [001] in an Os4B4 framework. The structure was refined using the superspace approach. The basic structure of the Y subsystem can be idealized as having I4/mmm symmetry, with a crystallographically unique Y atom located on the 4/mmm position. The actual superspace symmetry is P42/nmc(00σ3)s0s0. The Y atoms feature only subtle positional modulation in the [001] direction. The Os4B4 subsystem [P42/ncm(00σ3)00ss superspace symmetry] is built of columns of edge-sharing Os4 tetrahedra extending along [001] and B2 dumbbells. The Os4 tetrahedra feature pronounced positional modulation with a distinct variation of the Os—Os bond lengths. Modulation of the B2 dumbbells is best described as a rotation about the [001] axis. Full Article text
4 From `crystallographic accuracy' to `thermodynamic accuracy': a redetermination of the crystal structure of calcium atorvastatin trihydrate (Lipitor®) By journals.iucr.org Published On :: 2024-10-08 With ever-improving quantum-mechanical computational methods, the accuracy requirements for experimental crystal structures increase. The crystal structure of calcium atorvastatin trihydrate, which has 56 degrees of freedom when determined with a real-space algorithm, was determined from powder diffraction data by Hodge et al. [Powder Diffr. (2020), 35, 136–143]. The crystal structure was a good fit to the experimental data, indicating that the electron density had been captured essentially correctly, but two independent quantum-mechanical calculations disagreed with the experimental structure and with each other. Using the same experimental data, the crystal structure was redetermined from scratch and it was shown that it can be reproduced within a root-mean-square Cartesian displacement of 0.1 Å by two independent quantum-mechanical calculations. The consequences for the calculated energies and solubilities are described. Full Article text
4 Spin reorientation and the interplay of magnetic sublattices in Er2CuMnMn4O12 By journals.iucr.org Published On :: 2024-10-21 Through a combination of magnetic susceptibility, specific heat, and neutron powder diffraction measurements we have revealed a sequence of four magnetic phase transitions in the columnar quadruple perovskite Er2CuMnMn4O12. A key feature of the quadruple perovskite structural framework is the complex interplay of multiple magnetic sublattices via frustrated exchange topologies and competing magnetic anisotropies. It is shown that in Er2CuMnMn4O12, this phenomenology gives rise to multiple spin-reorientation transitions driven by the competition of easy-axis single ion anisotropy and the Dzyaloshinskii–Moriya interaction; both within the manganese B-site sublattice. At low temperature, one Er sublattice orders due to a finite f-d exchange field aligned parallel to its Ising axis, while the other Er sublattice remains non-magnetic until a final, symmetry-breaking phase transition into the ground state. This non-trivial low-temperature interplay of transition metal and rare-earth sublattices, as well as an observed k = (0, 0, ½) periodicity in both manganese spin canting and Er ordering, raises future challenges to develop a complete understanding of the R2CuMnMn4O12 family. Full Article text
4 Bond topology of chain, ribbon and tube silicates. Part II. Geometrical analysis of infinite 1D arrangements of (TO4)n− tetrahedra By journals.iucr.org Published On :: 2024-04-29 In Part I of this series, all topologically possible 1-periodic infinite graphs (chain graphs) representing chains of tetrahedra with up to 6–8 vertices (tetrahedra) per repeat unit were generated. This paper examines possible restraints on embedding these chain graphs into Euclidean space such that they are compatible with the metrics of chains of tetrahedra in observed crystal structures. Chain-silicate minerals with T = Si4+ (plus P5+, V5+, As5+, Al3+, Fe3+, B3+, Be2+, Zn2+ and Mg2+) have a grand nearest-neighbour 〈T–T〉 distance of 3.06±0.15 Å and a minimum T⋯T separation of 3.71 Å between non-nearest-neighbour tetrahedra, and in order for embedded chain graphs (called unit-distance graphs) to be possible atomic arrangements in crystals, they must conform to these metrics, a process termed equalization. It is shown that equalization of all acyclic chain graphs is possible in 2D and 3D, and that equalization of most cyclic chain graphs is possible in 3D but not necessarily in 2D. All unique ways in which non-isomorphic vertices may be moved are designated modes of geometric modification. If a mode (m) is applied to an equalized unit-distance graph such that a new geometrically distinct unit-distance graph is produced without changing the lengths of any edges, the mode is designated as valid (mv); if a new geometrically distinct unit-distance graph cannot be produced, the mode is invalid (mi). The parameters mv and mi are used to define ranges of rigidity of the unit-distance graphs, and are related to the edge-to-vertex ratio, e/n, of the parent chain graph. The program GraphT–T was developed to embed any chain graph into Euclidean space subject to the metric restraints on T–T and T⋯T. Embedding a selection of chain graphs with differing e/n ratios shows that the principal reason why many topologically possible chains cannot occur in crystal structures is due to violation of the requirement that T⋯T > 3.71 Å. Such a restraint becomes increasingly restrictive as e/n increases and indicates why chains with stoichiometry TO<2.5 do not occur in crystal structures. Full Article text
4 Structural and biochemical characterization of the M405S variant of Desulfovibrio vulgaris formate dehydrogenase By journals.iucr.org Published On :: 2024-05-01 Molybdenum- or tungsten-dependent formate dehydrogenases have emerged as significant catalysts for the chemical reduction of CO2 to formate, with biotechnological applications envisaged in climate-change mitigation. The role of Met405 in the active site of Desulfovibrio vulgaris formate dehydrogenase AB (DvFdhAB) has remained elusive. However, its proximity to the metal site and the conformational change that it undergoes between the resting and active forms suggests a functional role. In this work, the M405S variant was engineered, which allowed the active-site geometry in the absence of methionine Sδ interactions with the metal site to be revealed and the role of Met405 in catalysis to be probed. This variant displayed reduced activity in both formate oxidation and CO2 reduction, together with an increased sensitivity to oxygen inactivation. Full Article text
4 Preliminary X-ray diffraction and ligand-binding analyses of the N-terminal domain of hypothetical protein Rv1421 from Mycobacterium tuberculosis H37Rv By journals.iucr.org Published On :: 2024-06-27 Mycobacterium tuberculosis can reside and persist in deep tissues; latent tuberculosis can evade immune detection and has a unique mechanism to convert it into active disease through reactivation. M. tuberculosis Rv1421 (MtRv1421) is a hypothetical protein that has been proposed to be involved in nucleotide binding-related metabolism in cell-growth and cell-division processes. However, due to a lack of structural information, the detailed function of MtRv1421 remains unclear. In this study, a truncated N-terminal domain (NTD) of MtRv1421, which contains a Walker A/B-like motif, was purified and crystallized using PEG 400 as a precipitant. The crystal of MtRv1421-NTD diffracted to a resolution of 1.7 Å and was considered to belong to either the C-centered monoclinic space group C2 or the I-centered orthorhombic space group I222, with unit-cell parameters a = 124.01, b = 58.55, c = 84.87 Å, β = 133.12° or a = 58.53, b = 84.86, c = 90.52 Å, respectively. The asymmetric units of the C2 or I222 crystals contained two or one monomers, respectively. In terms of the binding ability of MtRv1421-NTD to various ligands, uridine diphosphate (UDP) and UDP-N-acetylglucosamine significantly increased the melting temperature of MtRv1421-NTD, which indicates structural stabilization through the binding of these ligands. Altogether, the results reveal that a UDP moiety may be required for the interaction of MtRv1421-NTD as a nucleotide-binding protein with its ligand. Full Article text
4 First crystal structure of the DUF2436 domain of virulence proteins from Porphyromonas gingivalis By journals.iucr.org Published On :: 2024-09-26 Porphyromonas gingivalis is a major pathogenic oral bacterium that is responsible for periodontal disease. It is linked to chronic periodontitis, gingivitis and aggressive periodontitis. P. gingivalis exerts its pathogenic effects through mechanisms such as immune evasion and tissue destruction, primarily by secreting various factors, including cysteine proteases such as gingipain K (Kgp), gingipain R (RgpA and RgpB) and PrtH (UniProtKB ID P46071). Virulence proteins comprise multiple domains, including the pro-peptide region, catalytic domain, K domain, R domain and DUF2436 domain. While there is a growing database of knowledge on virulence proteins and domains, there was no prior evidence or information regarding the structure and biological function of the well conserved DUF2436 domain. In this study, the DUF2436 domain of PrtH from P. gingivalis (PgDUF2436) was determined at 2.21 Å resolution, revealing a noncanonical β-jelly-roll sandwich topology with two antiparallel β-sheets and one short α-helix. Although the structure of PgDUF2436 was determined by the molecular-replacement method using an AlphaFold model structure as a template, there were significant differences in the positions of β1 between the AlphaFold model and the experimentally determined PgDUF2436 structure. The Basic Local Alignment Search Tool sequence-similarity search program showed no sequentially similar proteins in the Protein Data Bank. However, DaliLite search results using structure-based alignment revealed that the PgDUF2436 structure has structural similarity Z-scores of 5.9–5.4 with the C-terminal domain of AlgF, the D4 domain of cytolysin, IglE and the extracellular domain structure of PepT2. This study has elucidated the structure of the DUF2436 domain for the first time and a comparative analysis with similar structures has been performed. Full Article text
4 Human transforming growth factor β type I receptor in complex with kinase inhibitor SB505124 By journals.iucr.org Published On :: 2024-10-23 The crystal structure of the intracellular domain of transforming growth factor β type I receptor (TβR1) in complex with the competitive inhibitor SB505124 is presented. The study provides insights into the structure and function of TβR1 in complex with SB505124, and as such offers molecular-level understanding of the inhibition of this critical signalling pathway. The potential of SB505124 as an avenue for therapy in cancer treatment is discussed on basis of the results. Full Article text
4 The cadmium oxidotellurates(IV) Cd5(TeO3)4(NO3)2 and Cd4Te5O14 By journals.iucr.org Published On :: The crystal structure of Cd5(TeO3)4(NO3)2 exhibits a distinct layered arrangement, whereas Cd4Te5O14 crystallizes with a framework structure. Full Article text
4 Crystal structures of two polymorphs for fac-bromidotricarbonyl[4-(4-methoxyphenyl)-2-(pyridin-2-yl)thiazole-κ2N,N']rhenium(I) By journals.iucr.org Published On :: Crystallization of the title compound from CH2Cl2/n-pentane (1:5 v/v) at room temperature gave two polymorphs, which crystallize in monoclinic (P21/c; α form) and orthorhombic (Pna21; β form) space groups. The ReI complex molecules in either polymorph adopt a six-coordinate octahedral geometry with three facially-oriented carbonyl ligands, one bromido ligand, and two nitrogen atoms from one chelating ligand ppt-OMe. In the crystal, both polymorph α and β form di-periodic sheet-like architectures supported by multiple hydrogen bonds. Full Article text
4 Crystal structure, Hirshfeld surface, DFT and molecular docking studies of 2-{4-[(E)-(4-acetylphenyl)diazenyl]phenyl}-1-(5-bromothiophen-2-yl)ethanone; a bromine⋯oxygen type contact By journals.iucr.org Published On :: The title compound is a non-liquid crystal molecule. The molecular crystal is consolidated by C—Br⋯O&z-dbnd;C type contacts running continuously along the [001] direction. Full Article text
4 Synthesis, crystal structure and Hirshfeld surface analysis of N-(4-methoxyphenyl)picolinamide By journals.iucr.org Published On :: The molecular and crystal structure of N-(4-methoxyphenyl)picolinamide were studied and Hirshfeld surfaces and fingerprint plots were generated to investigate various intermolecular interactions. Full Article text
4 Crystal structures of two polymorphs for fac-bromidotricarbonyl[4-(4-methoxyphenyl)-2-(pyridin-2-yl)thiazole-κ2N,N']rhenium(I) By journals.iucr.org Published On :: 2024-11-08 Crystallization of the title compound, fac-[ReBr(ppt-OMe)(CO)3] (ppt-OMe = C15H12N2OS), from CH2Cl2/n-pentane (1:5 v/v) at room temperature gave two polymorphs, which crystallize in monoclinic (P21/c; α form) and orthorhombic (Pna21; β form) space groups. The ReI complex molecules in either polymorph adopt a six-coordinate octahedral geometry with three facially-oriented carbonyl ligands, one bromido ligand, and two nitrogen atoms from one chelating ligand ppt-OMe. In the crystal, both polymorph α and β form di-periodic sheet-like architectures supported by multiple hydrogen bonds. In polymorph α, two types of hydrogen bonds (C—H...O) are found while, in polymorph β, four types of hydrogen bonds (C—H...O and C—H...Br) exist. Full Article text
4 Heitt Mjölnir: a heated miniature triaxial apparatus for 4D synchrotron microtomography By journals.iucr.org Published On :: 2024-01-01 Third- and fourth-generation synchrotron light sources with high fluxes and beam energies enable the use of innovative X-ray translucent experimental apparatus. These experimental devices access geologically relevant conditions whilst enabling in situ characterization using the spatial and temporal resolutions accessible at imaging beamlines. Here, Heitt Mjölnir is introduced, a heated miniature triaxial rig based on the design of Mjölnir, but covering a wider temperature range and larger sample volume at similar pressure capacities. This device is designed to investigate coupled thermal, chemical, hydraulic and mechanical processes from grain to centimetre scales using cylindrical samples of 10 mm × 20 mm (diameter × length). Heitt Mjölnir can simultaneously reach confining (hydraulic) pressures of 30 MPa and 500 MPa of axial stress with independently controlled sample pore fluid pressure < 30 MPa. This internally heated apparatus operates to temperatures up to 573 K with a minimal vertical thermal gradient in the sample of <0.3 K mm−1. This new apparatus has been deployed in operando studies at the TOMCAT (Swiss Light Source), I12 JEEP (Diamond Light Source) and PSICHÉ (Synchrotron SOLEIL) beamlines for 4D X-ray microtomography with scan intervals of a few minutes. Heitt Mjölnir is portable and modular, allowing a wide range of 4D characterizations of low-grade metamorphism and deformational processes. It enables spatially and temporally resolved fluid–rock interaction studies at conditions of crustal reservoirs and is suitable for characterization of material properties in geothermal, carbonation or subsurface gas storage applications. Technical drawings and an operation guide are included in this publication. Full Article text
4 Investigation of structural and reflective characteristics of short-period Mo/B4C multilayer X-ray mirrors By journals.iucr.org Published On :: 2024-02-09 The results of a study of the structural and reflective characteristics of short-period multilayer X-ray mirrors based on Mo/B4C at wavelengths 1.54 Å, 9.89 Å and 17.59 Å are presented. The period of the samples varied in the range 8–35 Å. The average widths of the interfaces were ∼3.5 and 2.2 Å at one and the other boundaries, with a tendency for weak growth with any decrease in the period. The interlayer roughness was ∼1 Å. The research results indicate promising prospects for the use of multilayer Mo/B4C mirrors for synchrotron applications. Full Article text
4 Operando double-edge high-resolution X-ray absorption spectroscopy study of BiVO4 photoanodes By journals.iucr.org Published On :: 2024-04-15 High energy resolution fluorescence detected X-ray absorption spectroscopy is a powerful method for probing the electronic structure of functional materials. The X-ray penetration depth and photon-in/photon-out nature of the method allow operando experiments to be performed, in particular in electrochemical cells. Here, operando high-resolution X-ray absorption measurements of a BiVO4 photoanode are reported, simultaneously probing the local electronic states of both cations. Small but significant variations of the spectral lineshapes induced by the applied potential were observed and an explanation in terms of the occupation of electronic states at or near the band edges is proposed. Full Article text
4 3D imaging of magnetic domains in Nd2Fe14B using scanning hard X-ray nanotomography By journals.iucr.org Published On :: 2024-05-21 Nanoscale structural and electronic heterogeneities are prevalent in condensed matter physics. Investigating these heterogeneities in 3D has become an important task for understanding material properties. To provide a tool to unravel the connection between nanoscale heterogeneity and macroscopic emergent properties in magnetic materials, scanning transmission X-ray microscopy (STXM) is combined with X-ray magnetic circular dichroism. A vector tomography algorithm has been developed to reconstruct the full 3D magnetic vector field without any prior noise assumptions or knowledge about the sample. Two tomographic scans around the vertical axis are acquired on single-crystalline Nd2Fe14B pillars tilted at two different angles, with 2D STXM projections recorded using a focused 120 nm X-ray beam with left and right circular polarization. Image alignment and iterative registration have been implemented based on the 2D STXM projections for the two tilts. Dichroic projections obtained from difference images are used for the tomographic reconstruction to obtain the 3D magnetization distribution at the nanoscale. Full Article text
4 TEMPUS, a Timepix4-based system for the event-based detection of X-rays By journals.iucr.org Published On :: 2024-07-23 TEMPUS is a new detector system being developed for photon science. It is based on the Timepix4 chip and, thus, it can be operated in two distinct modes: a photon-counting mode, which allows for conventional full-frame readout at rates up to 40 kfps; and an event-driven time-stamping mode, which allows excellent time resolution in the nanosecond regime in measurements with moderate X-ray flux. In this paper, the initial prototype, a single-chip device, is introduced, and the readout system described. Moreover, and in order to evaluate its capabilities, some tests were performed at PETRA III and ESRF for which results are also presented. Full Article text
4 The diamond–silicon carbide composite Skeleton® as a promising material for substrates of intense X-ray beam optics By journals.iucr.org Published On :: 2024-08-06 The paper considers the possibility of using the diamond-silicon carbide composite Skeleton® with a technological coating of polycrystalline silicon as a substrate for X-ray mirrors used with powerful synchrotron radiation sources (third+ and fourth generation). Samples were studied after polishing to provide the following surface parameters: root-mean-square flatness ≃ 50 nm, micro-roughness on the frame 2 µm × 2 µm σ ≃ 0.15 nm. The heat capacity, thermal conductivity and coefficient of linear thermal expansion were investigated. For comparison, a monocrystalline silicon sample was studied under the same conditions using the same methods. The value of the coefficient of linear thermal expansion turned out to be higher than that of monocrystalline silicon and amounted to 4.3 × 10−6 K−1, and the values of thermal conductivity (5.0 W cm−1 K−1) and heat capacity (1.2 J K−1 g−1) also exceeded the values for Si. Thermally induced deformations of both Skeleton® and monocrystalline silicon samples under irradiation with a CO2 laser beam have also been experimentally studied. Taking into account the obtained thermophysical constants, the calculation of thermally induced deformation under irradiation with hard (20 keV) X-rays showed almost three times less deformation of the Skeleton® sample than of the monocrystalline silicon sample. Full Article text
4 Development and performance simulations of a soft X-ray and XUV split-and-delay unit at beamlines FL23/24 at FLASH2 for time-resolved two-color pump–probe experiments By journals.iucr.org Published On :: 2024-08-05 The split-and-delay unit (SDU) at FLASH2 will be upgraded to enable the simultaneous operation of two temporally, spatially and spectrally separated probe beams when the free-electron laser undulators are operated in a two-color scheme. By means of suitable thin filters and an optical grating beam path a wide range of combinations of photon energies in the spectral range from 150 eV to 780 eV can be chosen. In this paper, simulations of the spectral transmission and performance parameters of the filter technique are discussed, along with a monochromator with dispersion compensation presently under construction. Full Article text
4 Methyl 1-(4-fluorobenzyl)-1H-indazole-3-carboxylate By journals.iucr.org Published On :: 2023-11-23 The title compound, C16H13FN2O2, was synthesized by nucleophilic substitution of the indazole N—H hydrogen atom of methyl 1H-indazole-3-carboxylate with 1-(bromomethyl)-4-fluorobenzene. In the crystal, some hydrogen-bond-like interactions are observed. Full Article text
4 (E)-3-(1,3-Diphenyl-1H-pyrazol-4-yl)-1-(thiazol-2-yl)prop-2-en-1-one By journals.iucr.org Published On :: 2023-11-21 In the title molecule, C21H15N3OS, the C5=C6 double bond in the central enone group adopts a trans configuration. The dihedral angle between planes of the thiazole and pyrazole rings is 6.6 (2)°. In the crystal, pairs of C—H⋯O hydrogen bonds generate inversion dimers and another pair of C—H⋯N hydrogen bonds link the dimers into chains propagating along a-axis direction. Full Article text
4 Bis[1,3-bis(2,4,6-trimethylphenyl)imidazolium] bis(μ-cis-1,2-diphenylethene-1,2-dithiolato-κ2S,S':κS)bis[(cis-1,2-diphenylethene-1,2-dithiolato-κ2S,S')iron(III)] dimethyl& By journals.iucr.org Published On :: 2023-12-26 The molecular structure of the solvated title salt, (C21H25N2)2[Fe2(C14H10S2)4]·2C3H7NO reveals that the anion is situated on a crystallographic inversion center in the triclinic space group Poverline{1}. The title compound crystallizes utilizing a network of weak π-stacking interactions of phenyl rings pertaining to the dithiolene unit. Moreover, the acidic imidazolium H atoms [N—C(H)—N] display non-classical hydrogen-bonding interactions of the C—H⋯O type to the oxygen atoms of the N,N-dimethyl formamide solvent, and hydrogen atoms on the backbone of imidazolium rings display weak C—H⋯S interactions with the dithiolene sulfur atoms. Full Article text
4 trans-Dichloridobis[(S)-(−)-1-(4-methylphenyl)ethylamine-κN]palladium(II) By journals.iucr.org Published On :: 2024-01-12 The title complex, [PdCl2(C9H13N)2], comprises a single molecule in the asymmetric unit. The PdII atom is tetracoordinated by two N atoms from two trans-aligned organic ligands and two Cl ligands, forming a square-planar metal coordination environment. The distances from the ortho-H atoms on the phenyl ring to the central PdII atom fall within the range 4.70–5.30 Å, precluding any significant intramolecular Pd⋯H interactions. Full Article text
4 Dichlorido(4,7-dimethoxy-1,10-phenanthroline-κ2N,N')zinc(II) By journals.iucr.org Published On :: 2024-01-12 In the title complex, [ZnCl2(C14H12N2O2)], the ZnII atom is located on a twofold rotation axis and is fourfold coordinated by two chlorido ligands and a bidentate 4,7-methoxy-1,10-phenanthroline ligand in a distorted tetrahedral environment. Weak π–π stacking interactions between adjacent 4,7-dimethoxy-1,10-phenanthroline rings [centroid-to-centroid distances = 3.5969 (11) and 3.7738 (11) Å] contribute to the alignment of the complexes in layers parallel to (overline{2}01). Full Article text
4 Synthesis and structure of trans-bis(4-amino-3-nitrobenzoato-κO)bis(4-amino-3-nitrobenzoic acid-κO)diaquamanganese(II) dihydrate By journals.iucr.org Published On :: 2024-01-19 The manganese title complex, [Mn(C7H5N2O4)2(C7H6N2O4)2(H2O)2]·2H2O, is one of the first 4-amino 3-nitrobenzoic acid (4 A3NBA) monoligand metal complexes to be synthesized. It crystallizes in the centrosymmetric monoclinic space group P21/n with the complex molecules located on inversion centers. Four 4 A3NBA ligand molecules are monodentately coordinated by the Mn2+ ion through the carboxylic oxygen atoms while the other two positions of the inner coordination sphere are occupied by water molecules, giving rise to a distorted octahedron, and two water molecules are in the outer coordination sphere. There are two intramolecular hydrogen bonds in the complex molecule. The first is of the common N—H⋯O=N type, while the second is a rarely occurring very strong hydrogen bond in which a common proton is shared by two uncoordinated oxygen atoms of neighboring carboxylate groups. In the crystal, an intricate system of intermolecular hydrogen bonds links the complex molecules into a three-dimensional-network. Full Article text
4 Crystal structure of Ti4Ni2C By journals.iucr.org Published On :: 2024-01-19 Single crystals of the intermetallic phase with composition Ti4Ni2C were serendipitously obtained by high-pressure sintering of a mixture with initial chemical composition Ti2Ni. The Ti4Ni2C phase crystallizes in the Fdoverline{3}m space group and can be considered as a partially filled Ti2Ni structure with the C atom occupying an octahedral void. Ti4Ni2C is isotypic with Ti4Ni2O, Nb4Ni2C and Ta4Ni2C, all of which were studied previously by means of powder diffraction. Full Article text
4 (4-Butyl-1-ethyl-1,2,4-triazol-5-ylidene)[(1,2,5,6-η)-cycloocta-1,5-diene](triphenylphosphane)rhodium(I) tetrafluoridoborate By journals.iucr.org Published On :: 2024-01-26 In the title triazole-based N-heterocyclic carbene rhodium(I) cationic complex with a tetrafluoridoborate counter-anion, [Rh(C8H12)(C8H15N3)(C18H15P)]BF4, which crystallizes with two cations and two anions in the asymmetric unit, the Rh center has a distorted square-planar coordination geometry with expected bond distances. Several nonclassical C—H⋯F hydrogen-bonding interactions help to consolidate the packing. Two of the F atoms of one of the anions are disordered over adjacent sites in a 0.814 (4):0.186 (4) ratio. Full Article text
4 (2,2'-Bipyridine-κ2N,N')(4,4'-dimethoxy-2,2'-bipyridine-κ2N,N')palladium(II) bis(trifluoromethanesulfonate) By journals.iucr.org Published On :: 2024-02-08 In the title complex salt, [Pd(C10H8N2)(C12H12N2O2)](CF3SO3)2, the palladium(II) atom is fourfold coordinated by two chelating ligands, 2,2'-bipyridine and 4,4'-dimethoxy-2,2'-bipyridine, in a distorted square-planar environment. In the crystal, weak π–π stacking interactions between the 2,2'-bipyridine rings [centroid-to-centroid distances = 3.8984 (19) Å] and between the 4,4'-dimethoxy-2,2'-bipyridine rings [centroid-to-centroid distances = 3.747 (18) Å] contribute to the alignment of the complex cations in columns parallel to the b-axis direction. Full Article text
4 Prop-2-ynyl 3-methoxy-4-(prop-2-ynyloxy)benzoate By journals.iucr.org Published On :: 2024-02-27 The title compound, C14H12O4, comprises of two crystallographically independent molecules in the asymmetric unit, linked via C—H⋯O interactions to form dimeric entities. The allylic groups are twisted out of the phenyl planes with dihedral angles varying between 7.92 (13) and 25.42 (8)°. In the crystal, the packing follows a zigzag pattern along the c-axis direction. The absolute configuration of the sample could not be determined reliably. Full Article text
4 Crystal structure of defect scheelite-type Nd2/3[WO4] By journals.iucr.org Published On :: 2024-03-06 Neodymium(III) ortho-oxidotungstate(VI) was synthesized as a side-product in an unsuccessful synthesis attempt at fluoride derivatives of neodymium tungstate in fused silica ampoules, using neodymium(III) oxide, neodymium(III) fluoride and tungsten trioxide. Violet, platelet-shaped single crystals of the title compound emerged of the bulk, which crystallize in the defect scheelite type with a trigonal dodecahedral coordination of oxide anions around the Nd3+ cations and the hexavalent tungsten cations situated in the centers of oxide tetrahedra. Full Article text
4 cis,cis,cis-Dichloridobis(N4,N4-dimethylpyridin-4-amine-κN1)bis(dimethyl sulfoxide-κS)ruthenium(II) By journals.iucr.org Published On :: 2024-03-06 The structure of the title compound, [RuCl2(C7H10N2)2(C2H6OS)2], has monoclinic (P21/n) symmetry. The Ru—N distances of the coordination compound are influenced by the trans chloride or dimethylsulfoxide-κS ligands. The molecular structure exhibits disorder for two of the terminal methyl groups of a dimethyl sulfoxide ligand. Full Article text