Powder XRD Data Research Articles

Machine learning recognition of hybrid lead halide perovskites and perovskite-related structures from X-ray diffraction patterns.

Identification of crystal structures is a crucial stage in the exploration of novel functional materials. This procedure is usually time-consuming and can be false-positive or false-negative. This necessitates a significant level of expert proficiency in the field of crystallography and, especially, requires deep experience in perovskite-related structures of hybrid perovskites. Our work is devoted to the machine learning classification of structure types of hybrid lead halides based on available X-ray diffraction data. Here, we proposed a simple approach for quickly identifying the dimensionality of inorganic substructures, types of connections of lead halide polyhedra and structure types using common powder XRD data and a ML-decision tree classification model. The average accuracy of our ML algorithm in predicting the dimensionality of inorganic substructures, the type of connection of lead halide and inorganic substructure topology based on theoretically calculated XRD patterns among 14 most common structure types reached 0.76 ± 0.07, 0.827 ± 0.028 and 0.71 ± 0.05, respectively. To test the transferability of the developed ML model, we expanded our dataset to 30 structure types. The average accuracy of our ML algorithm in predicting the dimensionality of inorganic substructures, the type of connection of lead halide and inorganic substructure topology based on theoretically calculated XRD patterns among 30 structure types reached 0.820 ± 0.022, 0.74 ± 0.05 and 0.633 ± 0.018, respectively. The validation of our decision tree classification ML model on experimental XRD data shows accuracies of 1.0 and 0.82 for dimension and structure type prediction. Thus, our approach can significantly simplify and accelerate the interpretation of highly complicated XRD data for hybrid lead halides.

Easily Water-Synthesisable Iron-Chloranilate Frameworks as High Energy and High-Power Cathodes for Sustainable Alkali-Ion Batteries.

Achieving high battery performance from low-cost, easily synthesisable electrode materials is crucial for advancing energy storage technologies. Metal organic frameworks (MOFs) combining inexpensive transition metals and organic ligands are promising candidates for high-capacity cathodes. Iron-chloranilate-water frameworks are herein reported to be produced in aqueous media under mild conditions. Removal of reticular water from known [Fe2(CAN)3(H2O)4]·4H2O yields a new supramolecular metal-organic framework (SMOF), [Fe2(CAN)3(H2O)4]. Removing coordination water, a new 2D honeycomb-like MOF forms, Fe2(CAN)3, stable without counterions and solvent. This MOF adopts the unusual ABC layer-stacking, as determined using a combination of ab initio random structure searching, electron diffraction, and Rietveld refinement of powder XRD data. Magnetometry, Mossbauer and Raman spectroscopy confirm that all three [Fe2(CAN)3(H2O)x]·yH2O phases contain HS-Fe3+ and CAN2-, with magnetic ordering temperatures increasing (5→20K) as the Fe-CAN connectivity increases. The SMOF and MOF show reversible (de)insertion of >4Li+/f.u. at average 2.59 V and 2.76 V vs Li+/Li, respectively. [Fe2(CAN)3] achieves 146 mAh/g at 1C, thus specific energy (563 Wh/kg) and power (446 W/kg) in Li half-cells competitive with conventional LiFePO4 (~580 Wh/kg and ~450 W/kg). Beyond Li, [Fe2(CAN)3] delivers 394 Wh/kg and 421 Wh/kg, for Na and K half-cells respectively, becoming a competitive cathode for sustainable batteries.

Exploring a metal/base-free porphyrin involving a carboxyl-functionalized pyridine moiety for photocatalytic N-arylation of benzamide validated using RSM.

A porphyrin comprising a carboxyl-functionalized pyridine moiety was synthesized and characterized using 1H NMR, 13C NMR, FT-IR, powder-XRD, BET, ICP-MS, SEM and EDAX. The proton level (H0 = 1.19) and energy band gap (1.39 eV) were determined via UV-Vis spectrophotometry. The UV-visible and fluorescence emission spectra indicated the absorption window of the porphyrin photocatalyst with a distinct Soret band at 424 nm and four Q-bands at 517, 558, 595, and 649 nm. The existence of four Q-bands, the powder XRD data and the ICP-MS analysis supported the absence of metal in the porphyrin photocatalyst. The best photocatalytic conditions generated using Box-Behnken design of RSM (0.2 mol% PcCFP, 5 W LED, 1 : 1.2 ArX : ArCONH2, 24 h) were confirmed through the model reaction of benzamide and 1-bromo-4-nitrobenzene. The N-arylation of benzamide was achieved in a custom-built photoreactor at ambient conditions under exposure to 5 W LED light. Different ArX compounds comprising electron-repelling and electron-attracting groups were assessed to test the potential of the photocatalyst. The porphyrin was found to exhibit significant catalytic activity for C-N bond formation, resulting in 21-73% yields of the substituted benzanilide products. The N-arylated benzamide formation was confirmed using 1H NMR, 13C NMR, HR-MS and SC-XRD. Additionally, heteroaryl halides such as 2-bromo-, 3-bromo-, and 4-bromo-pyridine, as well as 2-chloro-4-methylpyridine, were also found to be compatible and provided admirable yields (28-67%). The stability and heterogeneous nature of the porphyrin photocatalyst were confirmed using FT-IR. The stability of the photocatalyst after the sixth run was demonstrated by the slight decline in the yield of the product from 71 to 67%. The formation of an aryl radical was detected using the scavenger TEMPO, which led to the achievement of N-arylated benzamides containing intermediates of industrial drugs.

Refining siliceous zeolite framework structures with 29Si 2D J-resolved NMR spectroscopy.

A modified shifted-echo PIETA pulse sequence is developed to acquire natural abundance 29Si 2D J-resolved spectra in crystalline silicates. The sequence is applied to the highly siliceous zeolites Sigma-2 and ZSM-12. The 2D J-resolved spectra are used to develop a silicate framework structure refinement strategy based on Si-O, O-O, and Si-Si distance restraints and analytical relationships between local structure and 29Si chemical shifts and geminal 2JSi-O-Si couplings. The refinement of the Sigma-2 structure showed that the Si-O and O-O distances were in excellent agreement with the single-crystal X-ray diffraction (SCXRD) data. The refinement of the ZSM-12 structure, initially determined from synchrotron powder XRD data, highlighted significant improvements in Si-O and O-O distances, and better agreement between calculated and experimental chemical shifts and J-couplings.

Ternary molybdate Rb5(Ag1/3Hf5/3)(MoO4)6: synthesis, structure, thermal expansion and ionic conductivity

This study aims to characterize the properties of the ternary molybdate Rb5(Ag1/3Hf5/3)(MoO4)6, which was previously identified during phase equilibrium investigations in the Ag2MoO4–Rb2MoO4–Hf(MoO4)2 system. A ternary molybdate Rb5(Ag1/3Hf5/3)(MoO4)6 was obtained through a solid-state reaction. It was found that the compound crystallizes in the trigonal space group R c and melts at 596 °C with decomposition. Its structure was refined using the Rietveld method. The crystal structure consists of a mixed framework composed of isolated (Ag/Hf)O6 octahedra and MoO4 tetrahedra, interconnected through shared oxygen vertices. Large voids within the framework accommodate two types of rubidium atoms. Using the powder XRD data recorded over 30–400 °C, the principal components of the thermal expansion tensor were determined. Rb5(Ag1/3Hf5/3)(MoO4)6 can be classified as a material with high thermal expansion coefficient (αV = 36.7∙10–6 °С–1 at 400 °C). At elevated temperatures, the compound exhibited significant ionic conductivity, reaching 1.7·10−3 S/cm at 480 °C with an activation energy Еа = 0.8 eV with oxygen ions as the probable charge carriers. Energy barriers for one-, two-, and three-dimensional transport in the compound were theoretically evaluated using the softBV program and bond valence sum maps (BVS).

Enhanced Quantum Efficiency via Co-Substitution in Red-Emitting Phosphor Sr2[MgAl5N7] : Eu2+ for Advanced Spectroscopic Applications Including Laser Displays with Ultra-High Luminescence Saturation Threshold.

In order to obtain novel and more efficient red light-emitting materials, a series of Sr2[Mg1-xLixAl5-xSixN7] : 0.01Eu2+ (SMAN-xLS, 0≤x≤0.5) red phosphors were devised and successfully synthesized via the high temperature solid state reaction and the effects of the co-substitution of [Mg-Al]5+ by [Li-Si]5+ on structural and luminescence properties is investigated in detail. A series of powder XRD data and Rietveld refinement indicate that [Li-Si]5+ co-substitution can successfully enter the Sr2[MgAl5N7] : 0.01Eu2+ (SMAN) lattice. With the entry of [Li-Si]5+ into the lattice, the substitution of Al3+ by Si4+ leads to the weakening of the nephelauxetic effect of the 5d level of Eu2+, which shifts the emission peak from 657 nm to 647 nm and reduces the excitation in the green region, i.e., lowers the absorption of green light. When the amount of [Li-Si]5+ co-substitution is x=0.1, the luminescence intensity and thermal stability of the sample are enhanced, in which the external quantum efficiency (EQE), reflecting the luminescence intensity, is elevated by 49.6 %. The increase in lattice rigidity gives rise to higher luminescence intensity, and the introduced trap levels for the compensation of luminescence enhances the thermal stability. Under blue laser excitation, the SMAN-0.1LS can achieve an ultra-high luminescence saturation threshold of 52.22 W/mm2, which is remarkably superior to other existing red phosphors, a breakthrough performance that has enormous potential for application in high-power laser display light sources. Cathodoluminescence (CL) characterization and measurements attest to the favorable CL properties of SMAN-0.1LS. By measuring the pressure-dependent luminescence of SMAN-0.1LS, the emission peak can be shifted from 650 nm to 702 nm with the increase of pressure, and the sensitivity dλ/dP is 5.07 nm/GPa, which is indicative of the potential application of this system as an optical pressure sensor.

Enhanced Quantum Efficiency via Co‐Substitution in Red‐Emitting Phosphor Sr2[MgAl5N7] : Eu2+ for Advanced Spectroscopic Applications Including Laser Displays with Ultra‐High Luminescence Saturation Threshold

AbstractIn order to obtain novel and more efficient red light‐emitting materials, a series of Sr2[Mg1−xLixAl5−xSixN7] : 0.01Eu2+ (SMAN‐xLS, 0≤x≤0.5) red phosphors were devised and successfully synthesized via the high temperature solid state reaction and the effects of the co‐substitution of [Mg−Al]5+ by [Li−Si]5+ on structural and luminescence properties is investigated in detail. A series of powder XRD data and Rietveld refinement indicate that [Li−Si]5+ co‐substitution can successfully enter the Sr2[MgAl5N7] : 0.01Eu2+ (SMAN) lattice. With the entry of [Li−Si]5+ into the lattice, the substitution of Al3+ by Si4+ leads to the weakening of the nephelauxetic effect of the 5d level of Eu2+, which shifts the emission peak from 657 nm to 647 nm and reduces the excitation in the green region, i.e., lowers the absorption of green light. When the amount of [Li−Si]5+ co‐substitution is x=0.1, the luminescence intensity and thermal stability of the sample are enhanced, in which the external quantum efficiency (EQE), reflecting the luminescence intensity, is elevated by 49.6 %. The increase in lattice rigidity gives rise to higher luminescence intensity, and the introduced trap levels for the compensation of luminescence enhances the thermal stability. Under blue laser excitation, the SMAN‐0.1LS can achieve an ultra‐high luminescence saturation threshold of 52.22 W/mm2, which is remarkably superior to other existing red phosphors, a breakthrough performance that has enormous potential for application in high‐power laser display light sources. Cathodoluminescence (CL) characterization and measurements attest to the favorable CL properties of SMAN‐0.1LS. By measuring the pressure‐dependent luminescence of SMAN‐0.1LS, the emission peak can be shifted from 650 nm to 702 nm with the increase of pressure, and the sensitivity dλ/dP is 5.07 nm/GPa, which is indicative of the potential application of this system as an optical pressure sensor.

Na3Sc(PO4)2: Thermal behaviors, distorted β-K2SO4-type structure and dielectric properties

The Na3Sc(PO4)2 (NSPO) compound was obtained by solid-state synthesis method and has a new type of distorted β-K2SO4 (arcanite) crystal structure that was refined based on powder XRD data in the space group (SG) P21/c, with unit cell parameters: a = 11.5533(1) Å, b = 5.31759(5) Å, c = 16.7650(2) Å, β = 97.6439(6)°. The NSPO is a metastable phase with an optimal synthesis temperature range between 1173 and 1233 K. When a mixture of Na2CO3, NH4H2PO4 and Sc2O3 is annealed below this temperature range, the NaSICON-type compound and Na-polyphosphates is formed. However, annealing above T∼1245 K leads to the decomposition onset into the NaSICON-type compound (Na3Sc2(PO4)3), Na3PO4 and terminates at T∼1289 K. NSPO phase is dielectric with σbulk = 4.4 × 10−7 S/cm at 300 K. Increasing the temperature from 300 to 1000 K leads to an increase in σbulk by four orders (σbulk = 5.6 × 10−3 S/cm at 1000 K).

Synthesis of Zintl Phase Metal Silicide Thermoelectric Materials in Magnesium/Zinc Flux.

Zintl phases have potential applications as thermoelectric materials for power generation and cooling owing to their complex crystal structures and unique electronic properties. We carried out reactions of silicon with barium and strontium in excess Mg/Zn flux to synthesize (Ba/Sr)5+xMg19-xSi12 Zintl phases, investigating the effect of varying Ba/Sr ratio on site mixing and thermoelectric properties. (Ba/Sr)5+xMg19-xSi12 compounds with 0 < x < 3 are charge-balanced Zintl phases which adopt the hexagonal Ho5Ni19P12 structure type (space group P6̅2m). Density of states calculations indicate that these materials are semimetals. Single-crystal X-ray diffraction data and elemental analysis for Ba5Mg19Si12, Ba4.86Sr2.94Mg16.20Si12, Ba3.63Sr4.20Mg16.17Si12, Ba1.93Sr5.99Mg16.08Si12, and Sr7.82Mg16.18Si12 show occupation of barium and strontium cations in Ho sites, while strontium mixes with magnesium on a specific Ni site. Powder XRD data of products show that they are single phase throughout the sample. Thermoelectric measurements indicate that increasing strontium content and mixing on three cation sites decreases thermal conductivity; it is hypothesized that improved overall thermoelectric behavior is likely due to the rattling of the Sr cations in their positions.

Understanding the Solid-State Structure of Riboflavin through a Multitechnique Approach.

Crystalline riboflavin (vitamin B2) performs an important biological role as an optically functional material in the tapetum lucidum of certain animals, notably lemurs and cats. The tapetum lucidum is a reflecting layer behind the retina, which serves to enhance photon capture and vision in low-light settings. Motivated by the aim of rationalizing its biological role, and given that the structure of biogenic solid-state riboflavin remains unknown, we have used a range of experimental and computational techniques to determine the solid-state structure of synthetic riboflavin. Our multitechnique approach included microcrystal XRD, powder XRD, three-dimensional electron diffraction (3D-ED), high-resolution solid-state 13C NMR spectroscopy, and dispersion-augmented density functional theory (DFT-D) calculations. Although an independent report of the crystal structure of riboflavin was published recently, our structural investigations reported herein provide a different interpretation of the intermolecular hydrogen-bonding arrangement in this material, supported by all the experimental and computational approaches utilized in our study. We also discuss, more generally, potential pitfalls that may arise in applying DFT-D geometry optimization as a bridging step between structure solution and Rietveld refinement in the structure determination of hydrogen-bonded materials from powder XRD data. Finally, we report experimental and computational values for the refractive index of riboflavin, with implications for its optical function.

Spin reorientation, spin switching, and magnetic compensation in Er1−xSmxFeO3 single crystals

We investigated spin reorientation, magnetic compensation and spin switching transitions in a series of high-quality single crystals of Er1−xSmxFeO3 (x = 0, 0.2, 0.4, 0.6, 0.8) prepared using the optical floating zone method. Structural and other preliminary characterizations confirmed the quality and phase purity of the crystals. Rietveld refinement of powder XRD data indicates that lattice parameters a and c increase linearly with increasing Sm concentration, whereas b remained constant. Field-cooled cooling (FCC) measurements revealed a temperature-induced spin reorientation transition (SRT) from Γ4 (Gx, Ay, Fz) to Γ2 (Fx, Cy, Gz) for all the samples. SRT temperature increased with Sm concentration and spread widely above and below room temperature. Moreover, magnetic compensation is common to all the compositions but decreases as Sm doping increases. We also observe type-I spin switching in samples with x = 0, 0.2, and 0.4 at an applied field of 60 Oe under FCC protocol, with a reduction in spin switching temperature as Sm content increased. For Sm-rich samples (x = 0.6, 0.8), spin switching was absent at 60 Oe.

Electrical conductivity study of BaSb4Ti4O15 compound

The lead-free compound of antimony-based new layered structure BaSb4Ti4O15 compound is synthesised by high-temperature conventional technique with a calcination temperature of 830 °C. The analysis of X-ray diffraction data shows that the compound had a single-phase orthorhombic crystal system. The scanning electron microscopic analysis of the samples shows a uniform distribution of grains with a smaller number of voids on the surface of the pellet. Generally, different computerized software are used for structural analysis taking powder XRD data. In the process we have attempted to use Jana2006, Qualx, Profex, POWDMULT, FullProf Suit, MAUD and EXPO etc. softwares. It has been found that different softwares give different results. The analysis of structural parameters looks more reliable and consistent with other physical parameters. However, the other possibilities of the structure with large number of experimental data cannot be ruled out. The electrical conductivity of the compound is studied with the help of complex impedance spectroscopy in the frequency range of 1 kHz–103 kHz and temperature range from 30 °C to 500 °C. The conduction process is a thermally activated phenomenon, which is confirmed by AC conductivity versus absolute temperature graphs. The process of conduction in the studied compound is electronic in lower temperatures and conductivity is due to the hoping of the ions at higher temperatures. The conduction process is due to the hopping and non-Debye type which is confirmed by Jonscher’s universal power law. A study of both AC and DC conductivity study informs the negative temperature coefficient of resistance behaviour. The finding here broadens the family of Sb-modified layered structured material which was a class of ferroelectric with good conductivity values with possible application in the field of optoelectronics as well as in perovskite solar cell.

Synthesis, spectroscopic characterization, physicochemical properties, biological activity and docking study of Cu (II) and La (III) metal complexes with a Schiff base ligand

The current study reports the synthesis of Schiff base ligand, N'-(2,4-dihydroxyphenyl)(phenyl)methylene)-4-methylbenzohydrazide (HL) by reversible condensation reaction of primary amine with carbonyl compound. Further, Schiff base ligand was utilized to prepare the Cu(II) and La(III) metal complexes M1L and M2L, respectively. 1H NMR, powder X-ray diffraction, FTIR, elemental analysis and thermogravimetric studies were used to characterize the Schiff base ligand and its metal complexes. The data of 1H NMR and FTIR studies disclose that ligand exhibits isobidentate behavior and metal complexes formation through the significant peaks. The qualitative pattern of the distributed intensity and crystalline structure of the Cu and La complexes were observed by the powder XRD data. ESR spectra of the Cu(II) complex exhibits an axial type symmetry g|| > g⊥ > 2.0023. In addition, the zones of inhibition (mm) of the Schiff base ligand and its metal complexes against gram-positive and gram-negative bacteria such Enterococcus faecalis, Escherichia coli, and Bacillus subtilis were measured at least three times under identical conditions. Molecular docking method was used to establish the position of the links, energy account, and molecular distance that contribute to the interaction between the complexes. An interaction results show that the synthesized HL and its M1L, M2L complexes effectively interact with the protein receptor molecule, which has a positive impact on the free binding energy. From the data of interaction energy measurements M1L complex has significantly more stable interaction and lower binding energy than compare to M2L complex.

Crystal and electronic structures of the new ternary gallide Zr12Pd40−xGa31+y (x = 0–1.5, y = 0–0.5)

Zr12Pd40Ga31 was prepared from the elements by arc melting under argon and subsequent annealing at 870 K for 720 h. Single-crystal X-ray diffraction reveals that Zr12Pd40Ga31 crystallizes in a new hexagonal structure type: Pearson symbol (PS) hP166, space group P6/mmm, a = 18.7670(6) Ǻ, c = 8.6634(6) Ǻ). The crystal structure consists of three types of atomic layers – two flat sheets at z = 0 (layer A) and z = 0.5 (C) and one corrugated at z = 0.25 and z = 0.75 (B), which stack in the sequence … ABCB … along the [001] direction. The structure shows close vicinity to a series of hexagonal structures with PS hP164–hP171. These compounds show peculiar structural variability expressed in the different atomic occupations of the Wyckoff positions along and around the 3-fold and 6-fold axes. Homogeneity range and lattice parameters of new ternary compound Zr12Pd40−xGa31+y (x = 0–1.5, y = 0–0.5) have been refined from EDX and powder XRD data. Electronic structure calculations and bonding analysis have been performed for an idealized model revealing domination of the Pd–Ga and Ga–Ga interactions.

Structural, spectroscopic and morphology studies on green synthesized ZnO nanoparticles

Zinc oxide nanoparticles (ZnO NPs) were synthesised using Tabernaemontana divaricata flower extract (TFE) in different weight percentages by facile, eco-friendly and cost-effective green synthesis method. Formation and structure of the ZnO NPs were studied by powder XRD, FT−IR, Raman and TEM studies. The crystals formed are of hexagonal wurtzite structure with biological functional groups attached. Average crystallite size of the ZnO NPs (17.5−23.3 nm) was obtained from the analysis of powder XRD data which increased with increase of TFE amount while the estimated values of dislocation density and micro-strain exhibited an opposite behaviour. The optical (direct and indirect) energy band gap values estimated using UV–vis DRS spectral data decreased with increasing amount of TFE. The photoluminescence spectra for the ZnO NPs exhibited multiple peaks spread over the visible region with one peak in the NIR region indicating the existence of various defect levels of Zn and O. Position of these defect levels within the band gap was assigned which is significantly modulated by TFE. TFE amount-dependent peak shift and/or peak broadening were observed in the Raman spectra of the ZnO NPs which were correlated with the growing disorder in the crystals induced by the extract molecules. FESEM study showed the agglomerated NPs with quasi-spherical morphology. Particle size of the ZnO NPs was estimated from FESEM images. EDX study indicated that increased presence of TFE in ZnO decreased the oxygen content in the synthesised material. HRTEM study revealed the agglomeration of nanoparticles with single crystalline nature. Present study convincingly established that flower extract used for the green synthesis efficiently modified the structure and optical property, defect levels and morphology of the potentially useful ZnO nanoparticles.

New organic (Dye) Sensitized Solar Cells with ferric iron III oxide doped barium chromite (Fe2O3-BaCrO4)

A new organic Dye has been successfully synthesized by a slow evaporation method. A single crystal x-ray diffraction study confirms the crystal system and lattice parameters of E-2HM4N. Powder XRD and NMR data were used to determine the crystal structure. The crystal system is a monoclinic Pc space group. Thus, the PXRD analysis confirms the good crystallinity nature and purity. UV–Vis spectral analysis has been used to measure the optical absorption of E-2HM4N its confirmed by a semiconducting material and the band gap energy is 2.1 eV. The nano dimension morphology of the particle was confirmed by FESEM. The characterization is (I -V) relationships between Maximum Voltage (518 mV) and Maximum Current (1.6 mA) is calculated by efficiency 0.8%. According to a survey of the literature, binary metal oxide Fe2BaCrO7 with organic dye E-2HM4N is newly reported. A flexible DSSCs was successfully fabricated.

Physico-Chemical Study of Mn(II), Co(II), Cu(II), Cr(III), and Pd(II) Complexes with Schiff-Base and Aminopyrimidyl Derivatives and Anti-Cancer, Antioxidant, Antimicrobial Applications.

A new class of biologically active mineral complexes was synthesized by reacting the following metal salts: MnCl2·4H2O, CoCl2·6H2O, CuCl2·2H2O, CrCl3·6H2O, and PdCl2 respectively with 2-amino-4,6-dimethyl pyrimidine (ADMPY) and Schiff's base resulting from the condensation reaction between benzaldehyde with p-phenylenediamine and 2-hydroxy-1-naphthaldehyde as ligands have been synthesized and characterized on the basis of their CHN, thermal analysis, XRD, SEM and magnetic measurements along with their FT-IR and UV-vis spectra. The scanning electron microscope SEM measurements and the calculations on the powder XRD data indicate the nano-sized nature of the prepared complexes (average size 32-88 nm). The spectral data confirmed the coordinated ligand (HL) via a nitrogen atom of an azomethine group (-C=N-) and phenolic -OH group and NH2-ADMPY ligand with the metal ions. An octahedral geometry for all complexes has been proposed based on magnetic and electronic spectral data except Pd(II) complex, which has a tetrahedral geometry. Molecular modeling was performed for Cu(II) complex using the density functional method DFT/B3LYP to study the structures and the frontier molecular orbitals (HOMO and LUMO). The antioxidant of the complexes was studied using the 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radical-scavenging assays. The metal complexes were tested in vitro for anticancer activities against two cancer lines A-549 and MRC-5 cells. Cu(II) and Pd(II) complexes showed the highest cytotoxicity effect, comparable to that of other cis-platinum-based drugs. The complexes showed significant activity against fungi and bacteria.

Gamma ray irradiated binuclear and mononuclear transition metal complexes with polydentate ligand: Template synthesis, spectral, XRD, morphology, solid electrical conductivity and antimicrobial activity

In this work, new binuclear Fe(III), Ni(II) and mononuclear Cu(II) Schiff base complexes that obtained via template condensation of Fe(III), Ni(II) and Cu(II) chlorides with N1-(3-aminopropyl) propane-1,3-diamine and 1,3-diphenylpropane-1,3‑dione (1B, 2B, 3B), respectively were prepared and well investigated. The structure of the complexes was elucidated by means of microanalyses, various spectroscopic techniques (FT–IR, UV/Vis, X–ray diffraction), thermal (TG/DTG), molar conductivity and magnetic moment measurements, Fe(III), Ni(II) complexes have an octahedral structure, while Cu(II) complex adopts distorted square pyramidal geometry. To study γ– irradiation induced modifications, powder sample of these complexes was exposed to high energetic γ–ray irradiation at a dose of 20 kGy, (hereafter referred to as 1A, 2A, 3A, respectively). Physico-chemical properties of irradiated samples were also investigated by the aforementioned tools. The results revealed no remarkable change in the molar conductivity values and little shift of the peak position and the intensity for FT–IR and electronic spectra as a result of the distortion of lattice planes. Also, TG/DTG studies revealed decreasing in the thermal stability for all irradiated samples. From the powder XRD data for non-irradiated and γ–irradiated Ni(II) (2B, 2A) and Cu(II) (3B, 3A) complexes, average crystallite size (D) and dislocation density (δ) were calculated, the γ–irradiation resulted in decrease in the crystallite size for Ni(II) (2A) complex. The irradiated (3A) showed changes in the surface morphology compared to its non-irradiated one. The solid state electrical conductivity of non-irradiated and γ–irradiated Ni(II) complexes have been investigated. Furthermore, the non-irradiated samples (1B, 3B) and their γ–irradiated (1A, 3A) were assayed for their antibacterial property against Gram–positive as Staphylococcus aureus, Gram– negative as Escherichia coli and antifungal property against fungi as Candida albicans.

Structural analysis of Ba0.8Sr0.2Ti0.6Zr0.3Mn0.1O3 ceramics

Polycrystalline Ba0.8Sr0.2Ti0.6Zr0.3Mn0.1O3 was synthesized by solid-state reaction at 1600°C. The single phase formation of the compound without any impurities was confirmed by the X-ray diffraction technique. The prepared compound crystallized to a cubic structure with a space group of Pm-3m and the refined lattice parameters were a = b = c = 4.0253 Ǻ, α = β = γ = 90°. Rietveld refinement was carried for the powder XRD data using GSAS software and the experimental data peaks were indexed by Powder X software.

Phase and structural evolution of zirconolite ceramics prepared by solid-state reaction sintering

The evolution of phase assemblage and microstructure of stoichiometric zirconolite (CaZrTi 2 O 7 ) ceramics, prepared by a solid-state reaction sintering route, was systematically investigated as a function of sintering temperature. Using powder XRD and quantitative phase analysis data, it was determined that the formation of zirconolite was a one-step reaction, without formation of intermediate phases. The accompanying fractions of secondary CaTiO 3 and ZrO 2 phases were reduced to approximately 2 wt % each after sintering at 1200 °C, with zirconolite formed as the major phase (> 99 wt%) after reaction at 1300 °C. Notable product densification only occurred at T ≥ 1400 °C, at which it was possible to achieve a relative density of 96.97% which is highly desirable for applications as a nuclear wasteform. The zirconolite-2M polytype structure (space group: C2/c) was formed in all products as expected, confirmed by combined high resolution TEM-ED analyses.