The epitaxial growth of gaas using alkylarsine: Part 2. molecular orbital calculation

Semi-empirical molecular orbital calculations were carried out for the compounds (C₂H₅)₃As, (C₂H₅)₃Ga and RAsH₂ (R = C₂H₅, i-C₃H₇, i-C₄H₉, and t-C₄H₉) by using the CNDO/2-U program, and their capability of β-elimination reaction is compared on the basis of the torsion energy to the transition state, electrostatic interactions and orbital overlapping between the central atom and the β-hydrogen, and bond order of the metal-carbon, and carbon-hydrogen bond. In the comparison of (C₂H₅)₃As with (C₂H₅)₃Ga, we found that the β-elimination of (C₂H₅)₃As could hardly be expected to take place in the thermal decomposition. The capability of β-elimination would be smaller in C₂H₅AsH₂ than that in (C₂H₅)₃As. Moreover when the ethyl group is replaced by a t-butyl group in RAsH₂, the β-elimination reaction appears to become more difficult and a large possibility for a radical process is suggested.     

Theoretical study on influence of ligand and solvent to CdS clusters

Based on the experimental zinc blende and wurtzite structures of CdS nanocrystals, five new CdS clusters (Cd₃S₃, (Cd₃S₃)₂, (Cd₃S₃)₃, Cd₄S₄ with C_2V, and Cd₄S₄ with T_D symmetry) are investigated via optimization of their original structures at B3LYP/Lanl2dz theoretical level. Through considering integration influence of solvent and ligand, our calculated Raman and absorption spectra can be consistent with the reported experimental results. First, our calculated Raman peaks of Cd₃S₃, Cd₄S₄ (T_D), (Cd₃S₃)₂, and (Cd₃S₃)₃ are within the range of 260–290 cm^?1, which is also reported by experiment. Subsequently, for deep researching five clusters, the absorption spectra of them are calculated using time‐dependent DFT method. The wavelengths of the absorption peaks, which is calculated in solvent, increase in the order Cd₃S₃, Cd₄S₄ (T_D), (Cd₃S₃)₂, and (Cd₃S₃)₃. Moreover, the wavelengths of absorption peaks shift to blue in solvent, compared with those without solvent. Furthermore, our clusters are smaller than the size of the smallest CdS nanocrystals, the calculated absorption spectra of five clusters in solvent show obvious blue shift than the wavelengths of absorption spectra of reported CdS nanocrystals. This is induced by the quantum size effect. Besides, we further investigated the influence of ligands to CdS unit in aqueous condition. Through structures and characters analysis of S? Cd? SR, we discovered that ligands took important role during the formation of CdS nanocrystals in aqueous synthesis. Calculated results of spectra, bond length, and Wiberg bond index (WBI) values show that different ligands have similar influence on CdS unit. Moreover, using WBI values, we also confirm that Cd atom has stronger interaction with S in nanocrystals than that with S atom in ligand. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Water‐soluble and Halogen‐free Hexaammine Complexes of Metal Ions of Group 9 – Synthesis,Crystal Structures,and Vibrational Spectra

Reaction of [M(NH₃)₆]Cl₃ (M = Co, Rh, Ir) and [Ir(NH₃)₅(OH₂)]Cl₃ with (NH₄)₂C₂O₄ · H₂O in aqueous solution resulted in the isolation of [M(NH₃)₆]₂(C₂O₄)₃ · 4 H₂O and [Ir(NH₃)₅(OH₂)]₂(C₂O₄)₃ · 4 H₂O, respectively. The complexes have been characterized by X‐ray crystallography, IR and UV/VIS spectroscopy. The isomorphous compounds crystallize in the orthorhombic space group Pnnm (No. 58). Four molecules of crystal water are involved in an extended three‐dimensional hydrogen bonding network. The librational modes of the lattice water around 600 cm^–1 allow the characterization of [Ir(NH₃)₆]₂(C₂O₄)₃ · 4 H₂O and [Ir(NH₃)₅(OH₂)]₂(C₂O₄)₃ · 4 H₂O, respectively, by IR spectroscopy. The band around 600 cm^–1 shows a significant frequency shift in the IR spectra of the hexaammine and aquapentaammine complex of iridium(III) and, by that, a distinction is possible.     

La2Ti6O15-CeTi21O38-PbTiO3 ceramics formed in gaseous penetration of La-Ce into PbTiO3 and their electric properties

The gaseous penetration of La-Ce into PbTiO₃ ceramics is reported. The compounds of La₂Ti₆O₁₅ and CeTi₂₁O₃₈ are formed and the new La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃ ceramics are prepared by the penetration of La and Ce in the gaseous state. The new ceramic materials have a significant change in electric properties. The room temperature resistivity decreases from 2.0×10¹⁰ to 0.248 Ω. m, and the grain resistance exhibits an obvious PTCR effect with the change of temperature. However, the grain boundary resistance decreases rapidly with increase in temperature. The change rule of the total resistance is similar to that of the grain boundary, and the PTCR effect disappears and the tendency of transition to a conductive body is manifest. The XPS analysis suggests that the particles that are Pb, Ti, La and Ce in La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃ ceramics all change their valence and lead to decreasing resistivity, and the bound energy peak values of elements in La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃ ceramics are also reported. The La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃ ceramics have a better thermal stability in high temperatures through TG-DTA analysis.     

Theoretical study on halide and mixed halide Perovskite solar cells: Effects of halide atoms on the stability and electronic properties

Increasing the stability of perovskite solar cells is one of the most important tasks in the photovoltaic industry. Thus, the structural, energetic, and electronic properties of pure CH₃NH₃PbI₃ and fully doped compounds (CH₃NH₃PbBr₃ and CH₃NH₃PbCl₃) in cubic and tetragonal phases were investigated using density functional theory calculations. We also considered the effects of mixed halide perovskites CH₃NH₃PbI₂X (where X = Br and Cl) and compared their properties with CH₃NH₃PbI₃. The DFT results indicate that the phase transformation from tetragonal to cubic phase decreases the band gap. The calculated results show that the X‐site ion plays a vital role in the geometrical stability and electronic levels. An increase in the band gap and a reduction in the lattice constants are more apparent in CH₃NH₃PbI₂X compounds (I > Br > Cl).     

Reactivity in the solid state between CoWO4 and RE2WO6 where RE = Sm, Eu, Gd

Reactivity in the solid state between CoWO₄ and some rare-earth metal tungstates RE₂WO₆ (RE = Sm, Eu, Gd) was investigated by the XRD method. Two families of new isostructural cobalt and rare-earth metal tungstates, Co₂RE₂W₃O₁₄ and CoRE₄W₃O₁₆, were synthesized. The Co₂RE₂W₃O₁₄ phases are formed by heating in air the CoWO₄ and RE₂WO₆ compounds mixed at the molar ratio 2:1, while the CoRE₄W₃O₁₆ phases are synthesized at the molar ratio of CoWO₄/RE₂WO₆ equals to 1:2. The Co₂RE₂W₃O₁₄ phases as well as the CoRE₄W₃O₁₆ compounds crystallize in the orthorhombic system. The Co₂RE₂W₃O₁₄ and CoRE₄W₃O₁₆ compound melt above 1150 °C. A melting manner of the Co₂RE₂W₃O₁₄ and CoRE₄W₃O₁₆ compounds was determined in an inert atmosphere. The formation of CoWO_4−x phase was observed during heating in an inert atmosphere.     

Synthese und Kristallstrukturen der Phosphanimin-Komplexe MCl2(Me3SiNPMe3)2 mit M = Zn und Co,und CoCl2(HNPMe3)2

Syntheses and Crystal Structures of the Phosphaneimine Complexes MCl₂(Me₃SiNPMe₃)₂ with M = Zn and Co, and CoCl₂(HNPMe₃)₂ The molecular complexes MCl₂(Me₃SiNPMe₃)₂ (M = Zn, Co) have been prepared by the reaction of the dichlorides of zinc and cobalt with Me₃SiNPMe₃ in CH₃CN and CH₂Cl₂, respectively, whereas the complex CoCl₂(HNPMe₃)₂ has been prepared by the reaction of CoCl₂ with NaF in boiling acetonitrile in the presence of Me₃SiNPMe₃. All complexes were characterized by IR spectroscopy and by crystal structure determinations. The complexes MCl₂(Me₃SiNPMe₃)₂ crystallize isotypically. ZnCl₂(Me₃SiNPMe₃)₂: Space group P2₁2₁2₁, Z = 4, 2677 observed unique reflections, R = 0.024. Lattice dimensions at ?70°C: a = 1243.6; b = 1319.0; c = 1464.7 pm. CoCl₂(Me₃SiNPMe₃)₂: Space group P2₁2₁2₁, Z = 4, 3963 observed unique reflections, R = 0,071. Lattice dimensions at ?80°C: a = 1236.3; b = 1317.4; c = 1457.6 pm. CoCl₂(HNPMe₃)₂ · CH₂Cl₂: Space group Pbca, Z = 8, 1354 observed unique reflections, R = 0.055. Lattice dimensions at ?80°C: a = 1247.3; b = 998.4; c = 2882.4 pm. All complexes have monomeric molecular structures, in which the metal atoms are coordinated in a distorted tetrahedral fashion by the two chlorine atoms and by the nitrogen atoms of the phosphaneimine molecules.     

Adsorption properties of hydrazine on pristine and Si-doped Al12N12 nano-cage

The interaction of hydrazine (N₂H₄) molecule with pristine and Si-doped aluminum nitride (Al₁₂N₁₂) nano-cage was investigated using the density functional theory calculations. The adsorption energy of N₂H₄ on pristine Al₁₂N₁₂ in different configurations was about –1.67 and –1.64 eV with slight changes in its electronic structure. The results showed that the pristine nano-cage can be used as a chemical adsorbent for toxic hydrazine in nature. Compared with very low sensitivity between N₂H₄ and Al₁₂N₁₂ nano-cage, N₂H₄ molecule exhibits high sensitivity toward Si-doped Al₁₂N₁₂ nano-cage so that the energy gap of the Si-doped Al₁₂N₁₂ nano-cage is changed by about 31.86% and 37.61% for different configurations in the Si_Al model and by about 26.10% in the Si_N model after the adsorption process. On the other hand, in comparison with the Si_Al model, the adsorption energy of N₂H₄ on the Si_N model is less than that on the Si_Al model to hinder the recovery of the nano-cage. As a result, the Si_N Al₁₂N₁₁ is anticipated to be a potential novel sensor for detecting the presence of N₂H₄ molecule.     

The decomposition of the oxalate precursor and the stability and reduction of the YBa2Cu4O8 superconductor studied by TG coupled with FTIR and by XRD

The 124 superconductor YBa₂Cu₄O₈ was prepared from the oxalate precursor Y₂(C₂O₄)₃. ·4BaC₂O₄·8CuC₂O₄·xH₂O at one atmosphere oxygen pressure. In O₂ the precursor decomposes in one step at 300°C and more gradually (300°–600°C) in Ar. The stability of the superconductor is strongly dependent on the gas atmosphere: in O₂ and in air there is no significant weight change as long as the temperature does not exceed 800°C, whereas in a 1% O₂-99%N₂ mixture decomposition starts at about 670°C with the formation of CuO and YBa₂Cu₃O_x withx<7. The reduction of YBa₂Cu₄O₈ in a 5% H₂-95% Ar mixture takes place in at least four major steps with formation of products such as Y₂O₃, BaO, Cu₂O, Cu, BaY₂O₄ and Ba₄Y₂O₇.     

Towards perfunctionalized dodecahedranes--en route to C20 fullerene

“One‐pot” substitution of the twenty hydrogen atoms in pentagonal dodecahedrane (C₂₀H₂₀) by OH, F, Cl, and Br atoms is explored. Electrophilic insertion of oxygen atoms with DMDO and TFMDO as oxidizing reagents ended, far off the desired C₂₀(OH)₂₀, in complex polyol mixtures (up to C₂₀H₁₀(OH)₁₀ decols, a trace of C₂₀H(OH)₁₉?). Perfluorination was successful in a NaF matrix but (nearly pure) C₂₀F₂₀ could be secured only in very low yield. “Brute‐force” photochlorination (heat, light, pressure, time) provided a mixture of hydrogen‐free, barely soluble C₂₀Cl₁₆ dienes in high yield and C₂₀Cl₂₀ as a trace component. Upon electron‐impact ionization of the C₂₀Cl₁₆ material sequential loss of the chlorine atoms was the major fragmentation pathway furnishing, however, only minor amounts of chlorine‐free C₂₀⁺ ions. “Brute‐force” photobrominations delivered an extremely complex mixture of polybromides with C₂₀HBr₁₃ trienes as the highest masses. The MS spectra exhibited exclusive loss of the Br substituents ending in rather intense singly, doubly, and triply charged C₂₀H_4–0^+(2+)(3+) ions. The insoluble ～C₂₀HBr₁₃ fraction (C₂₀Br₁₄ trienes as highest masses) obtained along a modified bromination protocol, ultimately allowed the neat mass selection of C₂₀^? ions. The C₂₀Cl₁₆ dienes and C₂₀H_0–3Br_14–12 tri‐/tetraenes, in spite of their very high olefinic pyramidalization, proved resistant to oxygen and dimerization (polymerization) but added CH₂N₂ smoothly. Dehalogenation of the respective cycloaddition products through electron‐impact ionization resulted in C_22–24H_4–8⁺⁽²⁺⁾ ions possibly constituting bis‐/tris‐/tetrakis‐methano‐C₂₀ fullerenes or partly hydrogenated C₂₂, C₂₃, and C₂₄ cages.     

The Temperature‐Composition Phase Equilibria in the Hg0.8Cd0.2Te‐HgI2 Pseudobinary System

The temperature‐composition phase equilibria of the Hg_0.8Cd_0.2Te‐HgI₂ system were investigated between about 100 and 800 °C using Debye‐Scherrer powder X‐ray diffraction techniques, differential thermal analysis, differential scanning calorimetry, and thermochemical and structural calculations. This system is a pseudobinary temperature‐ composition plane in the HgTe‐CdTe‐HgI₂ pseudoternary phase diagram. Measurable solid solutions of HgI₂ in Hg_0.8Cd_0.2Te with the cubic zinc blende‐type structure exist between about 290 and 700 °C, with a maximum solubility of 4.9 ± 0.3 mole‐% HgI₂ at 363 ± 3 °C. Further addition of HgI₂ to HgI₂‐saturated Hg_0.8Cd_0.2Te yields the formation of CdI₂, which reduces the mole fraction (x) of CdTe in the Hg_1—xCd_xTe host lattice. After sufficient HgI₂ is added, the host lattice is depleted in CdTe and forms Hg₃Te₂I₂ in addition to CdI₂. Phase fields containing the ternary compound Hg₃TeI₄, which we first observed in the HgTe‐HgI₂ system, also exist in the present system. Quaternary analogs of the known ternary compounds Hg₃Te₂I₂ and Hg₃TeI₄, i.e., Hg_3—yCd_yTe₂I₂ and Hg_3—yCd_yTeI₄, were not observed under present experimental conditions.     

Zn4Si2O7(OH)2H2O盐修饰的纳米Ru催化剂催化苯选择加氢制环己烯

利用沉淀法制备了纳米Ru催化剂,在ZnSO₄存在下考察了Na₂SiO₃·9H₂O和二乙醇胺作反应修饰剂对Ru催化剂催化苯选择加氢制环己烯性能的影响,并用X-射线衍射(XRD)、X-射线荧光光谱(XRF)和透射电镜-能量散射谱(TEM-EDS)等物理化学手段对加氢前后Ru催化剂进行了表征。结果表明,在水溶液中Na₂SiO₃与ZnSO₄可以反应生成Zn₄Si₂O₇(OH)₂H₂O盐、H₂SO₄和Na₂SO₄,化学吸附在Ru催化剂表面上的Zn₄Si₂O₇(OH)₂H₂O盐起着提高Ru催化剂环己烯选择性的关键作用。Na₂SiO₃·9H₂O量的增加,生成的Zn₄Si₂O₇(OH)₂H₂O盐逐渐增加,Ru催化剂的活性降低,环己烯选择性逐渐升高。向反应体系中加入二乙醇胺,它可以中和Na₂SiO₃与ZnSO₄反应生成的硫酸,使化学平衡向生成更多的Zn₄Si₂O₇(OH)₂H₂O盐的方向移动,导致Ru催化剂环己烯选择性增加。当Ru催化剂与ZnSO₄·7H₂O、Na₂SiO₃·9H₂O和二乙醇胺、分散剂ZrO₂的质量比为1.0:24.6:0.4:0.2:5.0时,2 g Ru催化剂上苯转化73%时环己烯选择性和收率分别为75%和55%,而且该催化剂体系具有良好的重复使用性和稳定性。     

Pulmonary toxicity of indium arsenide and arsenic selenide following repeated intratracheal instillations to the lungs of hamsters

Chronic toxicity of indium arsenide (InAs) and arsenic selenide (As₂Se₃) was studied in male Syrian golden hamsters which received InAs or As₂Se₃ particles, each containing a total dose of 7.5 mg of arsenic, by intratracheal instillations once a week for 15 weeks. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During their total lifespan, the cumulative body weight gain of the hamsters in the InAs group was suppressed significantly compared with that in the control group, but not in the As₂Se₃ group when compared with that in the control group. However, the survival rate for the InAs group was significantly higher compared with the control group, but not for the As₂Se₃ group when compared with the control group. During the animals' total lifespan, one lung adenoma was seen in the 27 hamsters in the InAs group and one lung adenoma in the 23 hamsters in the control group. No tumors of the lung were observed in the As₂Se₃ group. Malignant tumors outside the lung appeared in four hamsters in the InAs group and in two in the As₂Se₃ group. No non-lung malignant tumours were seen in the control group. Total tumor incidence rates were 25.9% (7/27) in the InAs group, 10.3% (3/29) in the As₂Se₃ group and 8.7% (2/23) in the control group. There were therefore no significant differences in tumor incidence between the InAs or the As₂Se₃ group, and the control group. Regarding histopathological findings in the lung, incidence rates of proteinosis-like lesions, pneumonia, metaplastic ossification and emphysema were seen only in the InAs group, and alveolar or bronchiolar cell hyperplasia observed in both the InAs and the As₂Se₃ groups were at significantly higher rates than those in the control group. From these results, it was concluded that InAs and As₂Se₃ particles could induce pulmonary toxicity when instilled intratracheally into hamsters. A great deal of attention should be paid to the toxicity of both InAs and As₂Se₃, even though in this study the adverse health effects of As₂Se₃ appeared to be less than those of InAs.     

Crystal structures of sodium magnesium selenate decahydrate,Na2Mg(SeO4)2·10H2O,a new selenate salt,and sodium magnesium selenate dihydrate,Na2Mg(SeO4)2·2H2O

Metal selenates crystallize in many instances in isomorphic structures of the corresponding sulfates. Sodium magnesium selenate decahydrate, Na₂Mg(SeO₄)₂·10H₂O, and sodium magnesium selenate dihydrate, Na₂Mg(SeO₄)₂·2H₂O, were synthesized by preparing solutions of Na₂SeO₄ and MgSeO₄·6H₂O with different molar ratios. The structures contain different Mg octahedra, i.e. [Mg(H₂O)₆] octahedra in the decahydrate and [MgO₄(H₂O)₂] octahedra in the dihydrate. The sodium polyhedra are also different, i.e. [NaO₂(H₂O)₄] in the decahydrate and [NaO₆(H₂O)] in the dihydrate. The selenate tetrahedra are connected with the chains of Na polyhedra in the two structures. O—H…O hydrogen bonding is observed in both structures between the coordinating water molecules and selenate O atoms.     

SO2 Resisting Pd-doped Pr1-xCexMnO3 Perovskites for Efficient Denitration at Low Temperature

H₂-SCR is served as the promising technology for the controlling of NO_x emission, and the Pd-based derivative catalyst exhibited high NO_x reduction performance. Effectively regulating the electronic configuration of the active component is favorable to the rational optimization of noble Pd. In this work, a series of Pr_1-xCe_xMn_1-yPd_yO₃@Ni were successfully synthesized and exhibited superior NO conversion efficiency at low temperatures. 92.7 % conversion efficiency was achieved at 200 °C over Pr_0.9Ce_0.1Mn_0.9Pd_0.1O₃@Ni in the presence of 4 % O₂ with a GHSV of 32000 h⁻¹. Meanwhile, the outstanding performance was obtained in the resistance to SO₂ (200 ppm) and H₂O (8 %). Deduced from the results of XRD, Raman, XPS, and H₂-TPR, the modification of d orbit states in palladium was confirmed originating from the incorporation in the B site of Pr_0.9Ce_0.1Mn_0.9Pd_0.1O₃. The existence of higher valence (Pd³⁺ and Pd⁴⁺) than the bivalence in Pr_0.9Ce_0.1Mn_0.9Pd_0.1O₃ catalyst was evidenced by XPS analysis. Our research provides a new sight into the H₂-SCR through the higher utilization of Pd.     

Difference in Conversions Between Dimethyl Sulfide and Methanethiol in a Cold Plasma Environment

This study compared the conversion of two malodorous substances, dimethyl sulfide (CH₃SCH₃, DMS) and methanethiol (CH₃SH) in a cold plasma reactor. The DMS and CH₃SH were successfully destroyed at room temperature. DMS decomposed less than CH₃SH at the same conditions. In oxygen-free condition, CS₂ and hydrocarbons were the major products, while SO₂ and CO_x were main compounds in oxygen-rich environments. The DMS/Ar plasma yielded more hydrocarbons and less CS₂ than that of CH₃SH/Ar plasma. In the CH₃SH/O₂/Ar plasma, rapid formation of SO and CO resulted in the yields much more amounts of SO₂ and CO₂ than those in the DMS/O₂/Ar plasma; and remained only a trace of total hydrocarbons, CH₂O, CH₃OH, CS₂, and OCS. The major differences between the reaction mechanisms of DMS and CH₃SH were also proposed and discussed.     

Reactions of Polyfluoroarenes with MenE‐MMe3 Reagents (MenE = Me2As,Me2P,Me2N,and MeS; M = Si,Sn): Synthesis of Polyfluoroaryl MenE Compounds

Trimethylsilyldimethylarsane Me₃SiAsMe₂ was used as a reagent for the substitution of fluorine in polyfluoroarenes C₆F₅X (X = F, H, Cl) and C₅NF₅ by the Me₂As group. The reactions occur between 50 — 180 °C, either in benzene or without solvent, to give as a rule 4‐X‐1‐(dimethylarsano)tetrafluorobenzenes XC₆F₄AsMe₂, ( 1—3 ) and 4‐dimethylarsano‐tetrafluoropyridine C₅NF₄AsMe₂ ( 4 ), respectively, in yields between 43 and 94 %. In the case of C₆F₆, also double substitution is observed affording 1, 4‐bis(dimethylarsano)tetrafluorobenzene 5 in addition to the monosubstituted derivative. The time and temperature dependencies of the reactions increase in the sequence: C₆F₆< C₆F₅H < C₆F₅Cl < C₅NF₅. The arsanes 1 and 4 were transformed to the potentially valuable bidentate ligands 1‐(dimethylarsano)‐4‐(dimethylphosphano)tetrafluorobenzene 6 and 4‐(dimethylarsano)‐2‐(dimethylphosphano)trifluoropyridine 8 by reaction with trimethylsilyl‐dimethylphosphane Me₃SiPMe₂. 6 reacts with oxygen to yield the corresponding phosphane oxide 7 . Trimethylsilyl‐dimethylamine Me₃SiNMe₂ also was successfully tested as a reagent for the dimethylamination of polyfluoroarenes C₆F₅X [X = F, H, Cl, CF₃, P(S)Me₂], 1‐P(S)Me₂‐4‐H‐C₆F₄ and 4‐X‐C₅NF₄ [X = F, PMe₂, P(S)Me₂]. Sulfuration of the new Me₂P derivatives 8 and 20 leads to the corresponding thiophosphanes 9 and 21 (Schemes 2 and 3). Furthermore, the recently reported very efficient one‐pot synthesis of Me₂P substituted polyfluoroarenes (e.g. XC₆F₄PMe₂ with X = F, Me₂PC₆F₄) was extended to the preparation of Me₂As and MeS derivatives of pentafluoropyridine using a mixture of Me₃SnH, As₂Me₄ (or S₂Me₂) and C₅NF₅ as precursors for the one‐pot reaction. The expected products 4‐(dimethylarsano)tetrafluoropyridine 4 and 4‐(methylthio)tetrafluoropyridine 22 , respectively, were obtained in 84 and 82 % isolated yields. The novel compounds were characterized by spectroscopic (NMR, MS) and analytical data. Compounds 5 , 7 , 9 and 21 could be isolated in form of single crystals and their structures have been studied by X‐ray diffraction.     

Oxalate-2-ethanolamine complexes of some bivalent cations (Mn,Co, Ni,Cu, Zn and Cd)

On the refluxing ofM(II) oxalate (M=Mn, Co, Ni, Cu, Zn or Cd) and 2-ethanolamine in chloroform, the following complexes were obtained: MnC₂O₄·HOCH₂CH₂NH₂·H₂O, CoC₂O₄·2HOCH₂CH₂NH₂, Ni₂(C₂O₄)₂·5HOCH₂CH₂NH₂·3H₂O, Cu₂(C₂O₄)₂·5HOCH₂CH₂NH₂, Zn₂(C₂O₄)₂·5HOCH₂CH₂NH₂·2H₂O and Cd₂(C₂O₄)₂·HOCH₂CH₂NH₂·2H₂O. Following the reaction ofM(II) oxalate with 2-ethanolamine in the presence of ethanolammonium oxalate, a compound with the empirical formula ZnC₂O₄·HOCH₂CH₂NH₂·2H₂O¹ was isolated. The complexes were identified by using elemental analysis, X-ray powder diffraction patterns, IR spectra, and thermogravimetric and differential thermal analysis. The IR spectra and X-ray powder diffraction patterns showed that the complexes obtained were not isostructural. Their thermal decompositions, in the temperature interval between 20 and about 900°C, also take place in different ways, mainly through the formation of different amine complexes. The DTA curves exhibit a number of thermal effects.     

Amorphous Li2O2: Chemical Synthesis and Electrochemical Properties

When aprotic Li–O₂ batteries discharge, the product phase formed in the cathode often contains two different morphologies, that is, crystalline and amorphous Li₂O₂. The morphology of Li₂O₂ impacts strongly on the electrochemical performance of Li–O₂ cells in terms of energy efficiency and rate capability. Crystalline Li₂O₂ is readily available and its properties have been studied in depth for Li–O₂ batteries. However, little is known about the amorphous Li₂O₂ because of its rarity in high purity. Herein, amorphous Li₂O₂ has been synthesized by a rapid reaction of tetramethylammonium superoxide and LiClO₄ in solution, and its amorphous nature has been confirmed by a range of techniques. Compared with its crystalline siblings, amorphous Li₂O₂ demonstrates enhanced charge‐transport properties and increased electro‐oxidation kinetics, manifesting itself a desirable discharge phase for high‐performance Li–O₂ batteries.     

Impact of Gd3+ and Nd3+ ions substitution on structural and magnetic properties of Co0.5Ni0.5Fe2O4 ferrite system

Co_0.5Ni_0.5(Gd/Nd)_xFe_2-xO₄ (x ?= ?0.0 and 0.06) ferrites were prepared by the solid-state reaction method. These materials were characterized by XRD, FT-IR spectroscopy, and VSM techniques. The XRD analysis revealed the phase formation of all samples and their cubic spinel structure with the Fd-3m space group. Lattice constant was found to increase due to Gd and Nd ions substitution. However, the crystallite size was observed to decrease by the substitution effect. The FT-IR spectra showed the two vibrational frequency bands of the tetrahedral and octahedral sites. From the magnetic properties study, it was identified that the pure and Gd substituted Co_0.5Ni_0.5Fe₂O₄ ferrite showed a ferromagnetic behaviour. While the Nd substituted Co_0.5Ni_0.5Fe₂O₄ ferrite delivered a superparamagnetic behaviour. The substitution of Gd and Nd changed the values of the magnetic parameters of Co_0.5Ni_0.5Fe₂O₄ ferrite. An increase in the saturation magnetization (M_s) value was observed due to substitution of Gd and Nd in Co_0.5Ni_0.5Fe₂O₄ ferrite, indicating that Gd and Nd substitution strengthen the supermagnetic interactions in Co_0.5Ni_0.5Fe₂O₄ ferrite. The highest value of M_s was observed in Gd doped sample.