Diffraction Data Research Articles

Supramolecular structure, DFT calculation and vibrational characterization of melamin-1-ium oxalurate monohydrate

Crystallization from an aqueous solution of melamine with parabanic acid was taken in a molar ratio of 1:1 leads to the formation of melamin-1-ium oxalurate monohydrate (MOX) crystals. The compound crystallizes in the centrosymmetric space group P21/n of the monoclinic system with four molecules per unit cell. The molecular geometry and vibrational frequencies of MOX in the ground state have been calculated by using the density functional hybrid function B3LYP 6–31+G(d) basis set. The results of optimized molecular structure are presented and compared with the experimental X-ray diffraction data. Furthermore, Fourier Transform Infrared (FT-IR) and Raman Spectra were used to conduct vibrational characterization to study the compound's structural groups. The calculated Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energies show that charge transfer occurs in the molecule and other related electronic properties have also been calculated. Besides, Molecular Electrostatic Potential (MEP) was performed to identify the possible electrophilic and nucleophilic sites. First order hyperpolarizability results establish the nonlinear response of the grown MOX crystal with respect to the electric field. Further, the crystal packing behaviour of MOX was studied quantitatively with the aid of Hirshfeld surface analysis.

Potent drug candidature of copper-coordinated metallodrug: Experimental study, spectroscopic insights, anticancer activity, apoptosis analysis, cell cycle, theoretical calculations, and molecular docking studies

The biological properties of the thiocarbohydrazone, pyrazole, and copper ions are well-known, thus copper complexes incorporated with pyrazole-thiocarbohydrazone hybrid ligands have potential medical applications. In this study, copper complex [Cu(PMT)2(Cl)2] derived from pyrazole-thiocarbohydrazone hybrid chelator (PMT) was successfully synthesized. With the help of several fundamental techniques, including elemental and thermal studies, molar conductivity, and magnetic moment measurements, the structure and coordination behavior of the PMT chelator and its Cu(PMT) nanocomplex were examined. In addition, records of ESR, FT-IR, and UV–Vis spectroscopy were obtained. The powder X-ray diffraction data has identified significant information about the crystalline forms of the Cu(PMT) chelate. The findings demonstrated that producing octahedral, mono-species of chelate and chelation occurs through the N, and S donor sites of neutral chelator. The cytotoxicity assessment of the PMT and its Cu(PMT) chelate was further evaluated against human ovary cancer cells (SKOV3), human breast cancer cells (MCF-7), and human colon cancer cells (HCT116) by using SRB assay. The Cu(PMT) chelate displayed promising results regarding standard doxorubicin. Furthermore, the apoptosis analysis of the Cu(PMT) chelate strongly induced the late-apoptotic cell population against the tested cancer cells. Also, the cell-cycle distribution of the Cu(PMT) complex arrests cell proliferation at the G1, S, and G2 phases. PMT and its Cu(PMT) were also studied using computational simulations and the DFT approach. Different chemical quantum parameters were determined from the optimized structure. The interaction between copper chelate and the CDK8 kinase active site was examined using docking studies.

Order-disorder phase transitions in Fe81Ga19-RE ALLOYS (RE = Dy, Er, Tb, Yb) according to neutron diffraction data

New data on the phase compositions and structural transformations in a number of Fe81Ga19 alloys doped with trace amount (≤ 0.2 at.%) of rare earth elements are presented. The data are obtained in neutron diffraction experiments performed with high resolution and in continuous temperature scanning mode when heated to 900 °C and subsequent cooling. It has been established that structural rearrangements proceed in a generally identical manner both in the original Fe81Ga19 alloy and in its doped analogues. Slow heating and subsequent cooling of the alloys (rate ±2 °C/min) leads to the formation of clusters of the D03 phase with sizes in the range (200–300) Å in the matrix of the disordered A2 phase. The sizes and volume fraction of clusters (~0.3 of the sample volume) weakly depend on the specific composition. The degree of ordering of the clusters atomic structure changes with temperature according to a second-order phase transition and is close to unity at room temperature. The search for structural ordering corresponding to the modified D03 phase, discovered in a number of electron diffraction studies, did not lead to a positive result.

RODIN: Raw Diffraction Data for Teaching, Training, and Demonstration

<i>RODIN</i>: Raw Diffraction Data for Teaching, Training, and Demonstration

Synthesis and Electrochemical Performance of High‐Entropy Spinel‐Type Oxides Derived from Multimetallic Polymeric Precursors

High‐entropy spinel‐type oxides are synthesized by a modified Pechini process, wet chemistry approach, and solid‐state synthesis method and characterized as anode materials for Li‐ion batteries. The Pechini process that involves chelation and polyesterification reactions facilitates the formation of high‐entropy spinel‐type oxides without compositional segregation at ≈600 °C as confirmed by in situ and ex situ XRD. XAFS analysis and the Rietveld refinement of room‐temperature neutron diffraction data suggest the composition (Mn0.05Fe0.48Co0.47, tetrahedral)(Cr0.61Mn0.52Fe0.11Co0.09Ni0.68, octahedral)O4 for phase‐pure specimens. Compared to high‐entropy spinel‐type oxides synthesized by the solid‐state method, the precursor‐derived materials demonstrate higher specific capacity as anodes, in which the materials without citric acid addition exhibit low capacity fading at high current densities and maintained a capacity of ≈200 mAh g−1 after 1000 cycles. The generation of a rock‐salt‐type phase during cycling is confirmed for the first time by in situ charging–discharging XRD. The charging–discharging of this anode material is achieved mainly through the embedding–disembedding of lithium ions in the lattice of the generated rock‐salt‐type phase.

Effects of ZnO additive on the electrical and densification properties of A-site deficient barium cerate perovskite

The dual strategies of A-site deficiency and addition of ZnO sintering aid have been employed to optimise stability and densify the high-temperature proton conductor Ba0.95Ce0.8Y0.2O3-δ at 1200 °C (B95CYZn-1200). Structural analysis performed by Rietveld refinement based on X-ray diffraction data indicated perovskite phase with monoclinic symmetry (space group, I2/m). Raman spectroscopy revealed the presence of ZnO for material sintered at 1200 °C, which most likely partially resides in grain-boundary regions, leading to enhanced electrical transport observed by impedance spectroscopy at low temperature. Anomalous and reproducible frequency-dependent impedance behaviour below 500 °C, observed in various atmospheres, is suggested to be attributable to the varistor-type properties of ZnO. The electrical conductivity of B95CYZn-1200 in the range 500–900 °C is typical of perovskite proton conductors but with greater conductivity than both Ba-stoichiometric BaCe0.8Y0.2O3-δ and ZnO-free Ba0.95Ce0.8Y0.2O3-δ in wet O2 and N2, reaching ∼ 1.1 S m−1 at 550 °C in wet O2. Resistance to carbonate formation and mechanical breakdown was demonstrated via prolonged impedance measurements in CO2- and H2-containing atmospheres in the range 600–700 °C.

Analysis of magnetic structures in JANA2020.

JANA2020 is a program developed for the solution and refinement of regular, twinned, modulated, and composite crystal structures. In addition, JANA2020 also includes a magnetic option for solving magnetic structures from powder and single-crystal neutron diffraction data. This tool uses magnetic space and superspace symmetry to describe commensurate and incommensurate magnetic structures. The basics of the underlying formulation of magnetic structure factors and the use of magnetic symmetry for handling modulated and non-modulated magnetic structures are presented here, together with the general features of the magnetic tool. Examples of structures solved in the magnetic option of JANA2020 are given to illustrate the operation and capabilities of the program.

Bonacinaite, Sc(AsO4) ⋅ 2H2O, the first scandium arsenate

Abstract. The new mineral bonacinaite (IMA2018-056), Sc(AsO4) ⚫ 2H2O, was found on the dumps of the Varenche Mine (Saint-Barthélemy, Nus, Aosta Valley, Italy), an old manganese mine, where it occurs as a low-temperature hydrothermal mineral associated mainly with quartz, granular braunite, undefined manganese oxides, arseniopleite, manganberzeliite and thortveitite. Bonacinaite forms colourless (with faint to distinct violet tints), pseudohexagonal, thick tabular crystals, up to 0.25 mm in size, sometimes with annular internal zones showing violet tinges, or as small, faintly violet lath-shaped crystals. The crystals are transparent and brittle, with vitreous lustre. The calculated density of an almost pure bonacinaite crystal is 2.82 g cm−3. Optically, bonacinaite is biaxial negative, α=1.598(4), β=1.618(3), and γ=1.638(3) (measured with a Na light source, 589 nm); 2V (measured) is large, and 2V (calculated) = −88.9°. The empirical formula, based on six O atoms per formula unit is (Sc0.90Mn3+0.08Fe3+0.01Pb0.01)Σ1.00[(As0.95P0.06)Σ1.01O4] ⚫ 2H2O. Bonacinaite has monoclinic symmetry, with space group P21/n and unit-cell parameters (single-crystal data / powder diffraction data) a=5.533(1)/5.521(1), b=10.409(2)/10.336(3), c=9.036(2)/9.059(4) Å, β=91.94(3)/91.97(4), V=520.1(2)/516.7(3) Å3 and Z=4. The crystal structure was refined from single-crystal intensity data obtained from a distinctly Al- and P-bearing crystal to R1(F) = 3.7 % for 1178 reflections. Bonacinaite is isotypic with the other members of the metavariscite group: kolbeckite, metavariscite and phosphosiderite.

Crystal structure of perfluorononanoic acid, C9HF17O2

The crystal structure of perfluorononanoic acid (PFNA) was solved via parallel tempering using synchrotron powder diffraction data obtained from the Brockhouse X-ray Diffraction and Scattering (BXDS) Wiggler Lower Energy (WLE) beamline at the Canadian Light Source. PFNA crystallizes in monoclinic space group P21/c (#14) with lattice parameters a = 26.172(1) Å, b = 5.6345(2) Å, c = 10.9501(4) Å, and β = 98.752(2)°. The crystal structure is composed of dimers, with pairs of PFNA molecules connected by hydrogen bonds via the carboxylic acid functional groups. The Rietveld-refined structure was compared to a density functional theory-optimized structure, and the root-mean-square Cartesian difference was larger than normally observed for correct powder structures. The powder data likely exhibited evidence of disorder which was not successfully modeled.

Structural elucidation of the dichloridodioxido-[(4,7-dimethyl)-1,10-phenanthroline]molybdenum(VI) (C14H12Cl2MoN2O2)

In this work, the synthesis, characterization, and X-ray powder diffraction data for dichloridodioxido-[(4,7-dimethyl)-1,10-phenanthroline]molybdenum(VI) are reported. The crystal structure of this compound was solved from powder diffraction data using the simulated annealing method with a subsequent refinement using the Rietveld method. The dioxo-molybdenum (VI) complex C14H12Cl2MoN2O2 crystallizes in a monoclinic system with space group C2/c (N° 15) with refined unit-cell parameters a = 12.9495 (5) Å, b = 9.7752 (4) Å,c = 12.0069 (6) Å, β = 101.702 (3) °, unit-cell volume V = 1488.27 (11) Å3, and values of Z′ = 0.5 and Z = 4. The molecules are organized into chains diagonally along the a and c axis. Parallel polyhedra are observed along these axes formed by the interactions of Mo, Cl, O, and N atoms present in the coordination sphere. The crystalline packing of this dioxo-molybdenum (VI) complex is dominated by five intermolecular hydrogen bonds, two intramolecular hydrogen bonds, and the four interactions between the centroids (CgI⋯CgJ) of the aromatic rings. An analysis of the Hirshfeld surface revealed that the greatest contributions of the attractive forces are given by H⋯Cl/Cl⋯H, H⋯C/C⋯H, H⋯O/O⋯H, and H⋯H interactions.

Structural Isomerism in Bimetallic Ag20Cu12 Nanoclusters.

Structural isomers of atomically precise metal nanoclusters are highly sought after for investigating structure-property relationships in nanostructured materials. However, they are extremely rare, particularly those of alloys, primarily due to the challenges in their synthesis and structural characterization. Herein, for the first time, a pair of bimetallic isomeric AgCu nanoclusters has been controllably synthesized and structurally characterized. These two isomers share an identical molecular formula, Ag20Cu12(C≡CR)24 (denoted as Ag20Cu12-1 and Ag20Cu12-2; HC≡CR is 3,5-bis(trifluoromethyl)phenylacetylene). Single-crystal X-ray diffraction data analysis revealed that Ag20Cu12-1 possesses an Ag17Cu4 core composed of two interpenetrating hollow Ag11Cu2 structures. This core is stabilized by four different types of surface motifs: eight -C≡CR, one Cu(C≡CR)2, one Ag3Cu3(C≡CR)6, and two Cu2(C≡CR)4 units. Ag20Cu12-2 features a bitetrahedron Ag14 core, which is stabilized by three Ag2Cu4(C≡CR)8 units. Interestingly, Ag20Cu12-2 undergoes spontaneous transformation to Ag20Cu12-1 in the solution-state. Density functional theory calculations explain the electronic and optical properties and confirm the higher relative stability of Ag20Cu12-1 compared to Ag20Cu12-2. The controlled synthesis and structural isomerism of alloy nanoclusters presented in this work will stimulate and broaden research on nanoscale isomerism.

X-ray powder diffraction data for mosapride dihydrogen citrate dihydrate

The previously unindexed laboratory X-ray powder diffraction data of mosapride dihydrogen citrate dihydrate, an API used to stimulate gastrointestinal motility, has been recorded at room temperature. Using these data, the crystal structure of this API has been refined in space group P21/c (No. 14) with a = 18.707(4) Å, b = 9.6187(1) Å, c = 18.2176(4) Å, β = 114.164(1)°, V = 2990.74(8) Å3, and Z = 4. The structure of this material corresponds to the phase associated with CSD Refcode LUWPOL determined at 93 K. The Rietveld refinement, carried out with TOPAS-Academic, proved the single nature of the sample and the quality of the data recorded.

Determination of the average crystallite size and the crystallite size distribution: the envelope function approach EnvACS.

A procedure is presented to exactly obtain the apparent average crystallite size (ACS) of powder samples using standard in-house powder diffraction experiments without any restriction originating from the Scherrer equation. Additionally, the crystallite size distribution within the sample can be evaluated. To achieve this, powder diffractograms are background corrected and long-range radial distribution functions G(r) up to 300 nm are calculated from the diffraction data. The envelope function f env of G(r) is approximated by a procedure determining the absolute maxima of G(r) in a certain interval (r range). Fitting of an ACS distribution envelope function to this approximation gives the ACS and its distribution. The method is tested on diffractograms of LaB6 standard reference materials measured with different wavelengths to demonstrate the validity of the approach and to clarify the influence of the wavelength used. The latter results in a general description of the maximum observable average crystallite size, which depends on the instrument and wavelength used. The crystallite site distribution is compared with particle size distributions based on transmission electron microscopy investigations, providing an approximation of the average number of crystallites per particle.

Bifacial perovskite/silicon heterojunction tandem solar cells based on FAPbI3-based perovskite via hybrid evaporation-spin coating

Combining the two technologies of tandem solar cells and bifacial solar cells has a great potential to maximize energy harvesting while minimizing material and surface usage. Mid-bandgap perovskites (1.50–1.60 eV) are important for fulfilling current matching in bifacial perovskite/silicon heterojunction tandem solar cells. Herein, efficient (>20 %) and stable planar FAPbI3-based perovskite (1.54 eV) solar cells have been fabricated via a hybrid evaporation-spin coating process. X-ray diffraction and electron microscopy data reveal the formation of highly crystalline (001) perovskite domains. The fabricated high-quality perovskite films lead to a more homogenized contact potential difference at the film surface and a reduction in non-radiative losses, resulting in a quasi-Fermi-level splitting (half-cell) of 1.16 eV, rendering 120 mV non-radiative losses. Transferring these films into tandem devices atop single-side textured silicon heterojunction bottom cells, we obtain an efficiency of >24 % under AM1.5 G illumination for monofacial devices with an active area of 1.21 cm2. Furthermore, the bifacial devices generate >27 mW cm−2 power output with 15 % rear illumination fraction.

Perovskite-Like Carbodiimides AB(NCN)3: Synthesis and Characterization of MnHf(NCN)3 and FeHf(NCN)3.

Two novel ternary air-stable transition-metal carbodiimides, MnHf(NCN)3 and FeHf(NCN)3, were synthesized via solid-state metathesis using either ZnNCN or Na2NCN as the carbodiimide source and the corresponding binary metal chlorides. These two phases are the first examples of transition-metal carbodiimides with an AB(NCN)3 composition, akin to ubiquitous ABO3 perovskite oxides. The crystal structure of MnHf(NCN)3 was determined and refined from powder X-ray diffraction (XRD) data in the non-centrosymmetric space group P6322 allowing for chirality, the assignment of which is supported by second-harmonic generation (SHG) measurements. FeHf(NCN)3 was found to crystallize isotypically, and the presence of iron(II) in a high spin state was confirmed by 57Fe Mößbauer spectroscopy. The structures are revealed to be NiAs-derived and can be described as a hexagonal stack of NCN2- anions with metal cations occupying 2/3 of the octahedral voids. Both IR spectroscopic measurements and DFT calculations agree that the NCN2- unit is a bent carbodiimide with C2v symmetry, necessary to account for the size difference present in such a vacancy-ordered structure. Magnetic studies reveal predominantly strong antiferromagnetic interactions but no long-range order between the paramagnetic Mn2+ centers, likely due to the dilution of Mn2+ over the octahedral sites or perhaps even due to some degree of magnetic frustration. The optical and electrochemical properties of MnHf(NCN)3 were then studied, revealing a wide band gap of 3.04 eV and p-type behavior.

Single pulse data collection with an X-ray chopper at in situ room temperature Laue crystallography beamline BL03HB

in situ room temperature Laue crystallography has gained increasing attention. This method is suitable for time-resolved Laue crystallography experiments to get crystal structure with only several single-frame data collections. To improve the diffraction efficiency of protein crystals at room temperature, a simple X-ray chopper combined with a fast shutter has been successfully developed and tested at in situ room temperature Laue crystallography beamline BL03HB of the Shanghai Synchrotron Radiation Facility (SSRF). This chopper is built with two aluminum blades. There are two windows on both blades, as well as an internal lead block. The width of windows for transmission of beam can be flexibly adjusted by a steel block coated with lead. The chopping frequency is controlled independently. The device allows chopping frequencies ranging from 0 to 10 Hz, and exposure times down to 100 μs can be obtained for our Laue diffraction experiment with the combination of a fast shutter. Moreover, a single pulse data collection strategy has been developed at BL03HB. The performance of our single pulse data collection method with the designed chopper for the improvement of data quality has been analyzed. Results show that the quality of diffraction data obtained from the single pulse data collection method is significantly improved, and the developed chopper is very suitable for room temperature Laue crystallography experiments at the synchrotron beamline with super bending magnet as light source.

Revealing the role of B-site cations in the antiferroelectricity of NaNbO3-based perovskites

The promising prospects of antiferroelectric perovskite oxides in the realm of energy storage applications hinge on the unique field-induced phase transitions. Once the transition is triggered by the application of an electric field, characteristic double polarization loops appear. However, NaNbO3-based materials that exhibit a reversible phase transition are still rare, which hinders the practical applications of lead-free antiferroelectrics. Here, the impact of materials chemistry on the competition between antiferroelectric and ferroelectric states is demonstrated in a series of NaNbO3-based solid solutions with varying perovskite B-site cations, while the A-site is fixed as strontium. The crystal structure is analyzed on the basis of Rietveld refinement of high-energy X-ray diffraction data. The phase transition behavior as well as the antiferroelectric and ferroelectric properties are probed by a series of electrical measurements. The antiferroelectric phase is universally observed for all investigated materials in the virgin state. The SrTiO3-substituted system shows an irreversible phase transition similar to that of pure NaNbO3. In contrast, double polarization hysteresis loops are observed in the SrHfO3-, SrZrO3-, and SrSnO3-substituted systems. It is confirmed that compounds that can reduce the tolerance factor of the system contribute to the stabilization of the antiferroelectric order, while those that can reduce the electronegativity difference lead to more pronounced double loops. The competition between antiferroelectricity and ferroelectricity is linked to the competition between covalent and ionic bonding in perovskites.

Integrated structural and functional analysis of Ba1-xSrxTiO3-Bi0.5Na0.5TiO3 ceramics: Insights into energy storage and electrocaloric performance

This paper reports an extensive investigation on the structural, dielectric, ferroelectric and pyroelectric properties of 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 (x = 0.0, 0.5, 0.6, 0.7) ceramics synthesized via conventional solid-state reaction (SSR) technique. X-ray diffraction data confirms the presence of pure perovskite phase. The variation of lattice parameters with strontium concentration in 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 ceramics were evaluated using the Rietveld refinement of the XRD data. The variation of dielectric permittivity with temperature (ε' ∼ T) shows the diffused phase transition and all the parameters related to the relaxor ferroelectrics (relaxation coefficient, activation energy and freezing temperature) were evaluated. The energy storage properties of the as-prepared ceramics were evaluated using the room temperature PE loop. Amongst the as-prepared ceramics, the composition with x = 0.5 possesses the highest energy storage density of 0.46 J/cm3 with an efficiency of 90 %. The temperature dependent P-E loops were used to study the electrocaloric effect (ECE). The ECE calculations were performed using in-direct method based on Maxwell's thermodynamic relations. A maximum adiabatic temperature change of 0.32 K is achieved at 268 K under a small applied electric field of 25 kV/cm for the ceramic with Sr content x = 0.5. Additionally, electrocaloric responsivity ξmax = 0.13 K mm/kV was also found for the studied ceramics. The above results show that the ceramic 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 with the composition x = 0.5 is a viable lead-free option for application in solid state refrigeration.

On the Structure of Tl2Pb(SO4)2 and Crystal Chemistry of Thallium‐Containing Sulfates

AbstractSingle crystal of a thallium‐containing sulfate Tl2Pb(SO4)2 was prepared through hydrothermal crystallization starting from Tl2CO3, Pb(NO3)2 and H2SO4. The crystal structure was solved from single‐crystal X‐ray diffraction data: Tl2Pb(SO4)2 crystallizes in space group R m with lattice parameters of a=5.5955(2) Å, c=22.1001(9) Å, and Z=3, which is also corroborated by Rietveld refinement on X‐ray powder data. The crystal structure can be regarded as [Pb(SO4)2]2− sheets intercalated by double layers of Tl+ along the c‐axis. From a mineralogical perspective, Tl2Pb(SO4)2 belongs to the palmierite family and can further be classified within palmierite‐supergroup. Validation of the structure models was carried out utilizing various concepts including Bond Valence (BV), Charge Distribution (CD) and Madelung Part of Lattice Energy (MAPLE). Notably, a contrast in stereochemical activity of 6s2 lone electron pair (LEP) between Tl+ and Pb2+ is interpreted in terms of bonding behaviours as well as Wang‐Liebau Eccentricity (WLE) parameters. Moreover, an extensive investigation into the crystal chemistry of thallium‐containing sulfates was conducted for the first time, focusing on the coordination environment and bonding behaviour of Tl+ and corresponding WLE parameters. A comparative analysis of these structurally related compounds including Tl2Pb(SO4)2, Tl3H(SO4)2, TlBi(SO4)2, TlIn(SO4)2, TlRh(SO4)2, and TlAl(SO4)2 was delineated.

Synthesis and crystal structure of acentric anhydrous beryllium carbonate Be(CO3).

The anhydrous alkaline earth metal carbonate Be(CO3) was synthesized in a laser-heated diamond anvil cell at moderate pressures and temperatures (20(2) GPa and 1500(200) K) by a reaction of BeO with CO2. It crystallizes in the acentric, trigonal space group P3121 with Z = 3. The crystal structure was obtained from synchrotron single crystal X-ray diffraction data and confirmed by density functional theory-based calculations in combination with Raman spectroscopy. Second harmonic generation measurements were employed to verify the acentric space group symmetry. The crystal structure of Be(CO3) is characterized by the presence of isolated [CO3]2--groups and BeO4-tetrahedra. This is a new structure type and such a topology has not been observed in carbonates before. Be(CO3) can be recovered to ambient conditions and is not undergoing a phase transition during decompression.