X-ray Powder Diffraction Data Research Articles

Crystal structure and thermodynamic properties of the new compound Sc4Sb2.52 in the Sc-Sb system

The new compound Sc4Sb2.52 was first discovered, which was synthesized by the arc-melting under high purity argon. The composition of the new compound was examined by energy dispersive X-ray spectroscopy (EDS). Its crystal structure was first determined using X-ray powder diffraction data by Rietveld method. In order to further verify its structure, it was also observed by transmission electron microscope (TEM). The compound crystallized in a cubic Th3P4-type structure with the space group I4¯3d (No. 220) and the lattice parameter is a = 8.65454(9) Å. Its atomic positions are Sc at 16c (0.0736(3), 0.0736(3), 0.0736(3)), and Sb at 12a (0.375, 0, 0.25). The heat capacity (Cp) of the new compound Sc4Sb2.52 was reported for the first time, which were measured using differential scanning calorimetry (DSC) in a temperature range from 105 K to 450 K. The curve of Cp shows the normal sigmoidal temperature dependence with no evidence of transitions and other anomalies, and which was fitted using Debye function from 0 K to 77 K and using Maier-Kelley type expression from 77 K to 450 K. The entropy, enthalpy and free-energy values were derived with integration of the heat capacities based on the relations of thermodynamic properties with Cp.

Hydrazine metal complexes as a single source in the mechanochemical preparation of metallic magnetic nanoparticles and investigation of their magnetic hyperthermia properties

Ferromagnetic metallic cobalt and nickel nanoparticles were synthesized by intramolecular metal-hydrazine ligand oxidation reduction reaction in basic media and the solid state. Nickel nanoparticles Ni1 and Ni2 are obtained from two complexes, Ni(N2H4)2(C2O4) and Ni(N2H4)2(HCO2)2, respectively. X-ray powder diffraction (XRD) and energy-dispersive X-ray (EDX) data show pure fcc crystal structures of nanoparticles. Scanning electron microscopy (SEM) images revealed both Ni1 and Ni2 nanoparticles have agglomerated sphere morphologies. The crystallite size estimated by using the Scherer method for Ni1 and Ni2 were 18.7 and 6.2 nm. Vibrating sample magnetometer (VSM) data show the coercivity of metallic nickel samples Ni1 and Ni2 are 50 and 153 Oe, respectively. Both nanoparticles cause an increase in the temperature of water under applied alternative magnetic field and showed specific loss power (SLP) of 70 W/g and 104.8 W/g, respectively. The same method is used in preparation of cobalt nanoparticles from two complexes, Co(N2H4)2(C2O4) and Co(N2H4)2(HCO2)2. XRD analysis data show both nanoparticles have hcp crystal structure. SEM images show nanosheet structure with sheet thickness of 10 to 30 nm. Coercivity of Co1 and Co2 nanoparticles obtained by VSM and Hc are 182 and 171 Oe, respectively. In spite of high coercivity in both Co1 and Co2 nanoparticles, the magnetic hyperthermia heating effects are not observed in practice and specific loss power (SLP) is zero.

X-Ray Diffraction and Structural Study of Ba1−xAExTiO3 Ceramics (AE: Ca, Mg and Sr for x=0,0.02,0.04,0.06 and 0.08)

By examining the X-ray powder diffraction data, the microstructure of the BaTiO3 ceramic modified by alkaline earth (AE) metals was characterized. Following profile fitting, the X-ray powder diffraction data of the powder mixtures were analyzed to estimate and evaluate the structural changes of the single-phase AE-modified BaTiO3. Each compound, as well as several polymorphic versions of the same compound, had a unique diffraction pattern, which was a coded representation of the crystal structure. The sole requirement for deciphering this data was the generation of exact data in order to enable phase identification, measurements of lattice parameters, atomic positions, etc. This work compares the various structural characteristics of void species nanostructure using X-ray diffraction with respect to the first sharp diffraction peak (FSDP) of different samples. Various parameters were computed using general expression and a comparison was presented in this paper.

New Findings on the Crystal Polymorphism of Imepitoin.

Scientific and industrial reasons dictate the study of the solid state of imepitoin, a highly safe and tolerable anticonvulsant drug used in the therapy of epileptic dogs that was approved in the Europe Union in 2013. Our investigations allowed us to discover the existence of a new polymorph of imepitoin, which finds itself in a monotropic relationship with the crystalline form (polymorph I) already known and present on the market. This form (polymorph II), obtained by crystallization from xylene, remains metastable under ambient conditions for at least 1 year. Both solid forms were characterized by thermal (DSC and TGA), spectroscopic (FT-IR and Raman), microscopic (SEM and HSM), and diffractometric techniques. The thermodynamic relationship between the two polymorphs (monotropic) is such that it is not possible to study the melting of polymorph II, not even by adopting appropriate experimental strategies. Our measurements highlighted that the melting peak of imepitoin actually also includes an onset of melt decomposition. The ab initio structure solution, obtained from synchrotron X-ray powder diffraction data collected at room temperature, allowed us to determine the crystal structure of the new polymorph (II). It crystallizes in the monoclinic crystal structure, P21/c space group (#14), with a = 14.8687(6) Å, b = 7.2434(2) Å, c = 12.5592(4) Å, β = 107.5586(8)°, V = 1289.61(8) Å3, and Z = 4.

Exotic Magnetism in Perovskite KOsO_{3}.

A new perovskite KOsO_{3} has been stabilized under high-pressure and high-temperature conditions. It is cubic at 500K (Pm-3m) and undergoes subsequent phase transitions to tetragonal at 320K (P4/mmm) and rhombohedral (R-3m) at 230K as shown from refining synchrotron x-ray powder diffraction (SXRD) data. The larger orbital overlap integral and the extended wave function of 5d electrons in the perovskite KOsO_{3} allow to explore physics from the regime where Mott and Hund's rule couplings dominate to the state where the multiple interactions are on equal footing. We demonstrate an exotic magnetic ordering phase found by neutron powder diffraction along with physical properties via a suite of measurements including magnetic and transport properties, differential scanning calorimetry, and specific heat, which provide comprehensive information for a system at the crossover from localized to itinerant electronic behavior.

Fe2−xCuxSnS4: Synthesis, structure and magnetic properties of a series of disordered spinels

Quaternary chalcogenides of compositions Fe2−xCuxSnS4 (x = 0.3, 0.4, 0.5, 0.6, 0.7) were synthesized at high temperature, 800 °C, in a sealed silica tube. All the compounds crystallized in the spinel structure type with cubic Fd−3 m space group. Both magnetic and nonmagnetic ions are disordered in these compounds with Fe/Sn occupies half of the octahedral voids while Fe/Cu occupies 1/8th of the tetrahedral voids as obtained from the Rietveld refinement of powder X-ray diffraction data. XPS study indicates that Fe exists in both +2 and + 3 oxidation states while Cu, Sn and S adopt +1, +4 and −2 oxidation states, respectively. Magnetic susceptibility study suggests ferrimagnetic like ordering in Fe1.6Cu0.4SnS4 below 230 K and the ordering temperature gradually decreases from 230 K to about 120 K with increase in Cu substitution. As the amount of Cu(I) increases in Fe2−xCuxSnS4, the percentage of Fe(III) increases to balance the charge. The magnetocaloric properties of polycrystalline Fe1.6Cu0.4SnS4 has been studied for their potential applications as magnetic refrigerant at cryogenic temperatures. With an applied magnetic field of 5 T, the maximum value of magnetic entropy change was found to be (Δ Sm) 0.4 Jkg−1K−1 with a relative cooling power (RCP) of 7 J kg−1. These values are very similar to the literature reported values for Fe based compounds. Further, manipulation at the Fe site may lead to enhancement of magnetocaloric effect for practical applications.

Structural analysis and Rietveld refinement of YCr1-xFexO3 (x=0, 0.5) perovskite samples calcined at two different temperatures

In the present work, we have synthesized polycrystalline YCr1-xFexO3 (x = 0, 0.5) perovskite samples using the traditional high-temperature solid-state reaction route (HT-SSRR) at two different temperatures for calcination (1000 °C as well as 1150 °C). The main objective of our investigation is to observe how these calcination temperatures impact the structural properties of the polycrystalline YCr1-xFexO3 (x = 0, 0.5) perovskite samples and reveal the comparative difference based on structural analysis and Rietveld refinement. The powder XRD analysis confirmed the presence of secondary phases, including Y2O3, Cr2O3, and Fe2O3, in the synthesized samples at both calcination temperatures. Notably, a higher calcination temperature (1150 °C) led to a reduction in the secondary phases and an increase in the crystalline size as determined by the Debye-Scherrer method (DSM). The FullProf software suite was used for performing a Rietveld refinement of the powder X-ray diffraction (PXRD) data. These findings suggest the crucial role of calcination temperature in tailoring the phase purity and crystallinity of YCr1-xFexO3 (x = 0, 0.5) perovskites.

Glass Sintering Aid Effect on Magnetic and Dielectric Properties of YFeO3 Ceramics

YFeO3 (YFO) and optimized glass wt% [0.5Li2O-0.5K2O-2B2O3 (LKBO) and BaO-Bi2O3-B2O3 (BBBO)] as a sintering aid in YFO ceramics were fabricated using fine powders prepared from sol-gel technique. Pure YFO and glass sintering aid added into YFO ceramics show orthorhombic crystal structure, confirmed by Rietveld refinement with the help of X-ray powder diffraction data. Scanning electron microscopy study revealed that the glass sintering aid added into YFO ceramics shows a higher average grain size than that of YFO ceramic. X-ray photoelectron spectroscopy was employed to confirm the presence of each atom/ion/element and their oxidation number in their respective samples. Using the Archimedes method, the density of the each ceramic sample was estimated. The BBBO glass sintering aid added into YFO exhibited a higher maximum magnetization value (2.82 emu g−1) compared to that of LKBO added into YFO (2.51 emu g−1) as well as pure YFO (1.53 emu g−1) ceramics. BBBO glass sintering aid added into YFO ceramic shows a higher dielectric constant, lower dielectric loss, and lower conductivity compared to LKBO added into YFO as well as pure YFO ceramics. In conclusion, improved magnetic and dielectric response of BBBO glasses added into YFO ceramic is a potential candidate for different dielectric-magnetic based applications.

Investigating spectroscopic properties, biological effects, and molecular docking studies of synthesized Schiff base metal complexes

In this current investigation, we have accomplished the synthesis of a Schiff base ligand termed (E)-4-methyl-N′-(2,4,5-trimethoxybenzylidene)benzohydrazide (HL) through a reversible condensation reaction, which engaged a carbonyl compound and a primary amine. This synthesized Schiff base ligand, HL, served as the foundation for the preparation of two metal complexes, namely, M1L (Cu complex) and M2L (La complex). To characterize these compounds, we employed various analytical techniques, including thermogravimetric studies, elemental analysis, powder X-ray diffraction, FT-IR spectroscopy and 1H NMR. The examination of powder X-ray diffraction data provided valuable insights into the crystalline structures of the Cu and La complexes. These shifts are indicative of structural changes in the complexes. Our electronic spectrum analysis revealed the pivotal involvement of the ligand in promoting charge transfer processes, substantiated by an increased concentration of charge transfer transitions observed when the ligand was present. Additionally, we evaluated the antibacterial efficacy of the Schiff base ligand HL and its metal complexes (Cu, La) against a spectrum of bacteria, encompassing both gram-positive (Bacillus subtilis, Enterococcus faecalis) and gram-negative (Escherichia coli) strains. In the current investigation, we utilized molecular docking techniques to explore the interactions between the synthesized HL and its M1L and M2L complexes with protein receptor molecules. These results highlighted the favorable binding energies and stable interactions of these compounds with the protein receptor, M1L displayed notably more stable interactions and lower binding energy compared to M2L. This suggests that M1L may have a stronger potential impact on the free binding energy and molecular interactions.

A glaserite-like ternary molybdate K(Mg0.5Zr0.5)(MoO4)2: Synthesis, thermal expansion, and ionic conductivity

A ternary molybdate K(Mg0.5Zr0.5)(MoO4)2 was successfully synthesized using the sol-gel method and traditional solid-phase reactions technique. The synthesis time reduced from 200 to 15 h and smaller particles (20–3 μm) were reached by the sol-gel method. Phase purity and crystal structure were confirmed by X-ray diffraction (XRD) analysis with Rietveld refinement. The surface morphology was characterized using a scanning electron microscope (SEM). Using the powder XRD data recorded over 30–550 °C, the principal components of the thermal expansion tensor were determined. K(Mg0.5Zr0.5)(MoO4)2 can be classified as a high-expansion material (αV = 160 × 10−6 °С−1 at 500°С). At elevated temperatures, the compound exhibits significant ionic conductivity, with values reaching 4.2·10−3 S/cm at 650°С, and oxygen ions are the probable charge carriers with activation energy Ea = 0.51 eV.

The Chemistry of Spinel Ferrite Nanoparticle Nucleation, Crystallization, and Growth.

The nucleation, crystallization, and growth mechanisms of MnFe2O4, CoFe2O4, NiFe2O4, and ZnFe2O4 nanocrystallites prepared from coprecipitated transition metal (TM) hydroxide precursors treated at sub-, near-, and supercritical hydrothermal conditions have been studied by in situ X-ray total scattering (TS) with pair distribution function (PDF) analysis, and in situ synchrotron powder X-ray diffraction (PXRD) with Rietveld analysis. The in situ TS experiments were carried out on 0.6 M TM hydroxide precursors prepared from aqueous metal chloride solutions using 24.5% NH4OH as the precipitating base. The PDF analysis reveals equivalent nucleation processes for the four spinel ferrite compounds under the studied hydrothermal conditions, where the TMs form edge-sharing octahedrally coordinated hydroxide units (monomers/dimers and in some cases trimers) in the aqueous precursor, which upon hydrothermal treatment nucleate through linking by tetrahedrally coordinated TMs. The in situ PXRD experiments were carried out on 1.2 M TM hydroxide precursors prepared from aqueous metal nitrate solutions using 16 M NaOH as the precipitating base. The crystallization and growth of the nanocrystallites were found to progress via different processes depending on the specific TMs and synthesis temperatures. The PXRD data show that MnFe2O4 and CoFe2O4 nanocrystallites rapidly grow (typically <1 min) to equilibrium sizes of 20-25 nm and 10-12 nm, respectively, regardless of applied temperature in the 170-420 °C range, indicating limited possibility of targeted size control. However, varying the reaction time (0-30 min) and temperature (150-400 °C) allows different sizes to be obtained for NiFe2O4 (3-30 nm) and ZnFe2O4 (3-12 nm) nanocrystallites. The mechanisms controlling the crystallization and growth (nucleation, growth by diffusion, Ostwald ripening, etc.) were examined by qualitative analysis of the evolution in refined scale factor (proportional to extent of crystallization) and mean crystallite volume (proportional to extent of growth). Interestingly, lower kinetic barriers are observed for the formation of the mixed spinels (MnFe2O4 and CoFe2O4) compared to the inverse (NiFe2O4) and normal (ZnFe2O4) spinel structured compounds, suggesting that the energy barrier for formation may be lowered when the TMs have no site preference.

Influence of annealing temperature on microstructure, magnetic and electrical properties of Ce doped cobalt ferrite nanoparticles

Cerium doped cobalt ferrite nanoparticles with chemical formula CoFe1·9Ce0·1O4 were synthesized at different annealing temperatures (600, 700, 800, 900 and 1000C°) via sol-gel auto-combustion method. Thermal analysis for sample annealed at 1000C° was examined through differential scanning calorimetry (DSC) and revealed the presence of exothermic peak at around 500C° attributed to crystallization of prepared nanoferrites. Structural analysis such as phase formation, crystallinity and morphology was investigated by x-ray powder diffraction (XRD) and high resolution transmission electron microscope (HRTEM). XRD study revealed higher dependence of grain size growth with annealing temperatures as compared to lattice parameter. HRTEM investigation confirmed that grains have almost uniform morphology with some agglomeration and confirmed values of lattice parameters and grain sizes calculated from XRD data. Magnetic hysteresis was studied by vibrating sample magnetometer (VSM) at room temperature with an applied field of 20 kOe. The results showed an increase in saturation magnetization and remanent magnetization with increasing of annealing temperature, whereas a decline in coercivity was observed. Distribution of cations at tetrahedral and octahedral sites was investigated using x-ray and magnetic parameters which confirmed the mixed spinel ferrite nature of samples. Dielectric properties were carried out at room temperature in the range 0.1Hz–3.0 MHz. Both dielectric constant and ac conductivity decreased with rising of annealing temperature. Variation of dielectric loss tangent, impedance, electric modulus and relaxation time with temperature were also investigated. The effect of annealing temperature on the structure and its impact on magnetic and dielectric properties has been examined and discussed.

Crystal structure of nicarbazin, (C13H10N4O5)(C6H8N2O)

The crystal structure of nicarbazin has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Nicarbazin is a co-crystal of 4,4′-dinitrocarbanilide (DNC) and 2-hydroxy-4,6-dimethylpyrimidine (HDP) molecules. Nicarbazin crystallizes in space group P-1 (#2) with a = 6.90659(8), b = 12.0794(4), c = 13.5040(7) Å, α = 115.5709(11), β = 102.3658(6), γ = 91.9270(4)°, V = 982.466(5) Å3, and Z = 2. The DNC and HDP molecules are linked by two strong N–H⋯O and N–H⋯N hydrogen bonds, and the HDP molecules are linked into centrosymmetric dimers by another N–H⋯O hydrogen bond. These strong hydrogen bonds link the molecules into layers parallel to the ab-plane and parallel stacking of both DNC and HDP molecules is prominent in the structure. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

Preparation of multicomponent rare earth based oxide charges

In this study we describe a relatively facile synthetic approach for the production of multicomponent oxide charges as the precursors of quaternary barium-rare earth-copper selenides BaRECuSe3, which, in turn, are of interest as promising thermoelectric materials. The starting reagents were initially prepared, including cleaning of the surface of elemental copper and annealing the rare earth oxides RE2O3 in a high-temperature furnace. A mixture of double, ternary and quaternary oxide charges was prepared by dissolving the stoichiometric ratios of the starting reagents RE2O3:2Cu:2Ba(NO3)2 (RE = La, Nd, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu), CeO2:Cu:Ba(NO3)2, Pr6O11:6Cu:6Ba(NO3)2 or Tb4O7:4Cu:4Ba(NO3)2 in nitric acid. The Ce-based oxide charge was obtained in the presence of H2O2 as a reducing agent to improve solubility in nitric acid. Then, cocrystallization of crystalline hydrates, followed by their dehydration, and destruction of the resulting (oxo)nitrate salts, and dispersion of the final polycrystalline samples were performed. According to the powder X-ray diffraction data, topochemical reactions led to the formation of heterometallic oxides BaxREyCuzOn, BaREO3, BaCuO2 and RE2CuO4. The developed synthetic approach allows to obtain the target phase of orthorhombic selenides BaRECuSe3 of three structural types BaLaCuS3, Eu2CuS3 and KZrCuS3 with high yields in a relatively short period of time and at lower temperatures in comparison to the previously used synthetic methods.

Size-Controlled Cu3VSe4 Nanocrystals as Cathode Material in Platinum-Free Dye-Sensitized Solar Cells.

In this work, we report the first single-step, size-controlled synthesis of Cu3VSe4 cuboidal nanocrystals, with the longest dimension ranging from 9 to 36 nm, and their use in replacing the platinum counter electrode in dye-sensitized solar cells. Cu3VSe4, a ternary semiconductor from the class of sulvanites, is theoretically predicted to have good hole mobility, making it a promising candidate for charge transport in solar photovoltaic devices. The identity and crystalline purity of the Cu3VSe4 nanocrystals were validated by X-ray powder diffraction (XRD) and Raman spectroscopy. The particle size was determined from the XRD data using the Williamson-Hall equation and was found in agreement with the transmission electron microscopy imaging. Based on the electrochemical activity of the Cu3VSe4 nanocrystals, studied by cyclic voltammetry, the nanomaterials were further employed for fabricating counter electrodes (CEs) in Pt-free dye-sensitized solar cells. The counter electrodes were prepared from Cu3VSe4 nanocrystals as thin films, and the charge transfer kinetics were studied by electrochemical impedance spectroscopy. The work demonstrates that Cu3VSe4 counter electrodes successfully replace platinum in DSSCs. CEs fabricated with the Cu3VSe4 nanocrystals having an average particle size of 31.6 nm outperformed Pt, leading to DSSCs with the highest power conversion efficiency (5.93%) when compared with those fabricated with the Pt CE (5.85%).

The crystal structure of charmarite – the first case of a 11 × 11 Å superstructure mesh in layered double hydroxides

Abstract Charmarite, Mn4Al2(OH)12CO3⋅3H2O, is a hydrotalcite supergroup member (or layered double hydroxide, LDH) with a previously unknown crystal structure and a Mn2+-analogue of quintinite (commonly erroneously reported as ‘2:1 hydrotalcite’). The single-crystal X-ray diffraction (XRD) data were obtained from the specimen from Mont Saint-Hilaire, Québec, Canada and are best processed in the space group P $\bar{3}$ , a = 10.9630(4), c = 15.0732(5) Å and V = 1568.89(12) Å3. The crystal structure has been solved by direct methods and refined to R1 = 0.0750 for 3801 unique reflections with Fo &gt; 2σ(Fo). The charmarite structure has long-range periodicity in the xy plane due to $2\sqrt 3$ a’ × $2\sqrt 3$ a’ scheme (or 11 × 11 Å) determined for LDHs for the first time (where a’ is a subcell parameter ≈ 3.2 Å). This periodicity is produced by the combination of two superstructures formed by: (1) Mn2+ and Al3+ ordering in the metal-hydroxide layers [Mn4Al2(OH)12]2+ according to the $\sqrt 3$ a’ × $\sqrt 3$ a’ pattern and (2) the (CO3)2– ordering according to the 2a’ × 2a’ pattern in the [CO3(H2O)3]2– interlayer sheet in order to avoid close contacts between adjacent carbonate groups. The $2\sqrt 3$ a’ × $2\sqrt 3$ a’ superstructure is an example of the adaptability of the components of the interlayer space to the charge distribution of the metal-hydroxyl layers. The Mn2+ and Al3+ cations have a large difference in size, which apparently leads to the considerable degree of their order as di- and trivalent cations resulting in a higher degree of statistical order of the interlayer components. Both powder and single-crystal XRD data show that the samples studied belong to the hexagonal branch of two-layer polytypes (2T or 2H) with d00n ≈ 7.57 Å. The chemical composition of the samples studied is close to the ideal formula. The Raman spectrum of charmarite is reported and the band assignment is provided.

Challenges in High-Throughput Inorganic Materials Prediction and Autonomous Synthesis

Materials discovery lays the foundation for many technological advancements. The prediction and discovery of new materials are not simple tasks. Here, we outline some basic principles of solid-state chemistry, which might help to advance both, and discuss pitfalls and challenges in materials discovery. Using the recent work of Szymanski [Nature 624, 86 (2023)], which reported the autonomous discovery of 43 novel materials, as an example, we discuss problems that can arise in unsupervised materials discovery and hope that by addressing these, autonomous materials discovery can be brought closer to reality. We discuss all 43 synthetic products and point out four common shortfalls in the analysis. These errors unfortunately lead to the conclusion that no new materials have been discovered in that work. We conclude that there are two important points of improvement that require future work from the community, as follows. (i) Automated Rietveld analysis of powder x-ray diffraction data is not yet reliable. Future improvement of such, and the development of a reliable artificial-intelligence-based tool for Rietveld fitting, would be very helpful, not only for autonomous materials discovery but also for the community in general. (ii) We find that disorder in materials is often neglected in predictions. The predicted compounds investigated herein have all their elemental components located on distinct crystallographic positions but in reality, elements can share crystallographic sites, resulting in higher-symmetry space groups and—very often—known alloys or solid solutions. This error might be related to the difficulty of modeling disorder in a computationally economical way and needs to be addressed both by computational and experimental material scientists. We find that two thirds of the claimed successful materials in Szymanski are likely to be known compositionally disordered versions of the predicted ordered compounds. We highlight important issues in materials discovery, computational chemistry, and autonomous interpretation of x-ray diffraction. We discuss concepts of materials discovery from an experimentalist point of view, which we hope will be helpful for the community to further advance this important new aspect of our field. Published by the American Physical Society 2024

Substantially low thermal conductivity and high thermoelectric figure-of-merit in Bi-doped Sr2CoRuO6 double perovskites

Transition metal oxide thermoelectric materials are interesting due to their high thermal stability, low toxicity, and low cost. Although several interesting thermoelectric oxides have been reported thus far, but reducing the lattice thermal conductivity while maintaining the good electrical conductivity to get optimum thermoelectric performance is still a challenge. In addition, many oxide systems are not well explored as yet for their potential to convert waste heat into electricity using the Seebeck effect. Herein, we report the structural and thermoelectric properties of the Sr2−xBixCoRuO6 (0 ≤ x ≤ 0.8) double perovskites. Rietveld refinement of X-ray powder diffraction data shows that the unit cell parameters increase with Bi content (x). The electrical resistivity decreases with x due to the much larger and well-connected grains in Bi containing samples. The Seebeck coefficient changes its sign from negative to positive with increasing Bi content indicating hole doping. The thermal conductivity of the samples decreases with increasing x due to the soft chemical bonding and heavy atomic mass of the doped Bi atoms. These changes in transport properties lead to a large power factor of 1.87 × 10–4 W/m·K2 and a thermoelectric figure-of-merit of 0.24 for the x = 0.8 sample at 668 K. We estimated the heat capacities from the temperature independent Dulong-Petit limit for solids for calculation of the thermal conductivities and therefore some uncertainty in the reported zT values is expected.

Crystal Structure of Nilotinib Hydrochloride Monohydrate According to Powder X-Ray Diffraction Data

Crystal Structure of Nilotinib Hydrochloride Monohydrate According to Powder X-Ray Diffraction Data

Proposed crystal structure of carbadox, C11H10N4O4

A model for the crystal structure of carbadox has been generated and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Carbadox crystallizes in space group P21 (#4) with a = 13.8155(3), b = 21.4662(1), c = 16.3297(3) Å, β = 110.0931(7)°, V = 4548.10(3) Å3, and Z = 16. The crystal structure is characterized by approximately parallel stacking of the eight independent carbadox molecules parallel to the bc-plane. There are two different molecular configurations of the eight carbadox molecules; five are in the lower-energy configuration and three are in a ~10% higher-energy configuration. This arrangement likely achieves the lowest-energy crystalline packing via hydrogen bonding. Hydrogen bonds link the molecules both within and between the planes. Each of the amino groups forms a N–H⋯O hydrogen bond to an oxygen atom of the 1,4-dioxidoquinoxaline ring system of another molecule. The result is four pairs of hydrogen-bonded molecules, which form rings with graph set R2,2(14). Variation in specimen preparation can affect the preferred orientation of particles considerably. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).