Miscibility of zinc sulfide and zinc phosphide

Solid solutions in the system zinc sulfide/zinc phosphide (Zn(2+)(x)S(2-2xP(2x)) were investigated using the cyclic cluster model within the semiempirical MSINDO method. Results of cyclic cluster calculations for binding energies of the perfect ZnS and Zn(3)P(2) are presented and compared with the experimental data. The miscibility of ZnS and Zn(3)P(2) over the whole composition range of 0 < x < 1 was investigated by calculating the Gibbs free energy of mixing Delta(M)G for different values of x. A miscibility gap was found at both ends of the composition range and compared with experimental data.     

Sorption and cytotoxicity of zinc on hydroxyapatite

The preparation, physicochemical properties, and cytotoxicity of zinc-containing hydroxyapatites (HAP) were considered for further using HAP as carriers for zinc-containing drugs and radiopharmaceuticals.     

Investigation of high current density on zinc electrodeposition and anodic corrosion in zinc electrowinning

Journal of Solid State Electrochemistry - In this work, the effects of high current density (500 A/m2, 600 A/m2, 700 A/m2, 800 A/m2) on zinc electrodeposition as well as the anodic corrosion...     

Contrasting melting behavior of zinc stearate and zinc oleate

The influence of a double bond in the middle of an otherwise flexible hydrocarbon chain on the melting of such assemblies has been investigated by comparing the melting behavior of zinc stearate and zinc oleate. By monitoring features in the infrared spectra that are characteristic of the global conformation of the hydrocarbon chain, it is shown that the double bond effectively decouples the thermal evolution of conformational disorder in the chain segments on either side of the double bond and the melting of each of these segments in the assembly occurs as independent events.     

Sorption of zinc and cadmium on zeolite rocks

The sorption of zinc and cadmium on zeolite rocks from different locations in Bulgaria is studied. The basic equilibrium and kinetic parameters are determined. It has been found that the clinoptilolite rock from the location Bali plast may be used as a sorbent for zinc and cadmium.     

Microwave synthesis of zinc sulfite and porous zinc oxide microrods

ZnSO(3) microrods with uniform size and shape can be prepared under microwave irradiation at much higher speed than a conventional heating bath, usually in minutes. The annealing of ZnSO(3) microrods produced porous ZnO microrods with pore size between 50-200 nm.     

Specifics of hydrothermal synthesis of oriented zinc oxide nanorods on metallic zinc substrates

Zinc oxide nanostructures are prepared hydrothermally in the presence of ethylenediamine (EDA). The morphology and photoluminescent properties of final products are studied as functions of synthesis temperature, synthesis time, and EDA concentration. A decrease in EDA concentration to 30% favors the formation of more perfect and more ordered structures. Blank experiments show that hydrothermal synthesis without organic reagents does not produce nanostructures. When samples are sheltered from convective flows in the cell, the rod growth direction is dictated by the grain orientation in the foil. When nanorods are formed under low supersaturations (in the absence of convective flows), oxygen nonstoichiometry arises in the nanorods and appears in photoluminescence spectra as increased peak intensities in the green spectral range.     

Deprotonation of zinc(II)-water and zinc(II)-alcohol and nucleophilicity of the resultant zinc(II) hydroxide and zinc(II) alkoxide in double-functionalized complexes: theoretical studies on models for hydrolytic zinc enzymes

The factors governing the deprotonation ability of zinc(II)-water and zinc(II)-alcohol and nucleophilicity of the resultant zinc(II) hydroxide and zinc(II) alkoxide as complex models for zinc enzymes have been investigated through Hartree-Fock and density-functional theory methods with the 6-311++G(d,p) basis set. Our calculations showed that in these double-functionalized complexes (i.e., zinc complexes having both a zinc(II)-alcohol motif and a zinc(II)-water motif) zinc(II)-alcohol is preferred in deprotonation over zinc(II)-water (i.e., zinc(II)-alcohol has a much lower pK(a) than zinc-coordinated water in the same molecule). Natural bond orbital analysis revealed that zinc(II) alkoxides are more nucleophilic than their respective counterparts zinc(II) hydroxides. The analysis of the transition state in the transformation reaction from zinc(II) hydroxide species to zinc(II) alkoxide species indicates that zinc(II) alkoxides are the preferred deprotonated species not only thermodynamically but also kinetically. Further examination of the proposed mechanisms of the zinc(II) alkoxide-promoted transesterification path and the zinc(II) hydroxide-promoted hydrolysis path revealed the structures of the intermediates and energy diagrams in the reactions. These results, entitled double-functionalized complexes, for the first time, put a firm theoretical foundation of why the zinc(II)-alcoholic OH is a better model for hydrolytic zinc enzymes (having both stronger acidity and better nucleophilicity).     

Phase transitions of adsorbed carboxylic acids on zinc oxide and of zinc soaps. Infrared and X-ray diffraction investigations

Summary The reaction between carboxylic acids in benzene solution and suspended zinc oxide particles was investigated by means of infrared spectrometry. The results show how the carboxyl groups react with the zinc oxide forming zinc carboxylate groups at the chemisorption. The chemisorbed acid forms a multilayer at the surface, which gives a new explanation of the protective action of adsorbed acids against flocculation of the particles in nonpolar solvents. The temperature-dependence of the spectra showed transitions at the same temperatures and of the same kind as the corresponding zinc carboxylates, whose spectra were also recorded. The zinc soaps exhibited thermotropic behaviour, and lyotrophy is suggested as the explanation of the multilayer formation.

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Zusammenfassung Mit Hilfe der Infrarotspektrometrie wurde die Einwirkung von Stearins?ure und ?ls?ure auf Zinkoxid untersucht, das in Benzol suspendiert worden war. Durch Carboxylatbildung wird eine multimolekulare Schicht der S?uren auf der Oberfl?che der Zinkpartikel ausgebildet. Die Partikel werden dadurch von der Flokkulation in nichtpolaren L?sungsmitteln geschützt. Die Temperaturabh?ngigkeit der Spektren entspricht der der Zinkcarboxylate.

     

Effect of salicylates and zinc salts on leukemic cells

Russian Chemical Bulletin - The prospects of the action of different types of chelating agents capable of binding to zinc, and salicylate ion comprising compounds on leukemic cells are reviewed....     

L—赖氨酸锌细胞生物学和生物学实验研究

研究了Ｌ－赖氨酸锌对健康大鼠血液及骨髓中细胞的影响,并与对照组进行了比较。结果表明,本品对健康鼠血液中红细胞,血小板,淋巴细胞、中性白细胞和单核细胞及骨髓多染红细胞中的微核数等均无显著性影响,另外大鼠伤寒沙门氏菌的致突变实验显示Ｌ－赖氨酸锌未引起大鼠伤寒沙门氏组氨酸缺陷型变异菌株的回复突变,而健康小儿血液各项生化指标的变化,揭示本品可显示提高血液中碱性磷酸酶和红细胞水平,对白细胞的增殖有促进作用,但对乳酸脱氢酶、谷丙转氨酶等无显著性影响。     

Separation of zinc and copper with cyanoacetamide in the determination of zinc

The new use of cyanoacetamide as a selective masking agent for copper in the determination of microgram amounts of zinc with zincon is described. It is very possible that the unique masking action of this compound may have importance in eliminating the interference of copper in other spectrophotometric and titrimetric procedures for zinc thereby reducing the time required to complete the analysis by decreasing or eliminating laborious separation or extraction techniques. The possibility of using cyanoacetamide as a masking agent for other ions should not be overlooked.     

The impact of physiological buffer solutions on zinc oxide nanostructures: zinc phosphate conversion

Zinc oxide (ZnO) nanostructures have been widely used in biosensor applications. However, little attention has been given to the interaction of ZnO structures with physiological buffer solutions. In the present work, it is shown that the use of buffers containing phosphate ions leads to the modification of the ZnO tetrapodal micro/nanostructures when immersed in such solutions for several hours, even at the physiological pH (7.4). ZnO samples designed to be used as transducers in biosensors were immersed in phosphate buffers for several durations at pH = 5.8 and pH = 7.4. Their detailed morphological, structural and optical characterization was carried out to demonstrate the effect of the ZnO interaction with the phosphate ions. The pH had an important role in the ZnO conversion into zinc phosphate, with lower pH promoting a more pronounced effect. After 72 h and at pH = 5.8, a significant amount of the ZnO structures were converted into crystalline zinc phosphate, while immersion during the same time at pH = 7.4 resulted predominantly in amorphous zinc phosphate particles mixed with the original ZnO tetrapods. Photoluminescence spectra show remarkable changes with prolonged immersion times, particularly when the luminescence of the sample was investigated at 14 K. These findings highlight the importance of a careful analysis of the sensing results when phosphate-based buffer solutions are in contact with the ZnO transducers, as the changes observed on the transduction signal during sensing experiments may also comprise a non-negligible contribution from a phosphate-induced transformation of ZnO, which can hamper an accurate assessment of the sensing behavior.     

Fast electrodeposition of zinc onto single zinc nanoparticles

The zinc deposition reaction onto metallic zinc has been investigated at the single particle level through the electrode-particle collision method in neutral solutions, and in respect of its dependence on the applied potential and the ionic strength of a sulphate-containing solution. Depending on the concentration of sulphate ions in solution, different amounts of metallic zinc were deposited on the single Zn nanoparticles. Specifically, insights into the electron transfer kinetics at the single particles were obtained, indicating an electrically early reactant-like transition state, which is consistent with the rate-determining partial de-hydration/de-complexation process. Such information on the reaction kinetics at the nanoscale is of vital importance for the development of more efficient and long-lasting nanostructured Zn-based negative electrodes for Zn-ion battery applications.

     

Effect of water vapor on the thermal decomposition process of zinc hydroxide chloride and crystal growth of zinc oxide

Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn₅(OH)₈Cl₂·H₂O, prepared by a hydrothermal slow-cooling method has been investigated by simultaneous X-ray diffractometry and differential scanning calorimetry (XRD-DSC) and thermogravimetric-differential thermal analysis (TG-DTA) in a humidity-controlled atmosphere. ZHC was decomposed to ZnO through β-Zn(OH)Cl as the intermediate phase, leaving amorphous hydrated ZnCl₂. In humid N₂ with P_H2O=4.5 and 10 kPa, the hydrolysis of residual ZnCl₂ was accelerated and the theoretical amount of ZnO was obtained at lower temperatures than in dry N₂, whereas significant weight loss was caused by vaporization of residual ZnCl₂ in dry N₂. ZnO formed by calcinations in a stagnant air atmosphere had the same morphology of the original ZHC crystals and consisted of the c-axis oriented column-like particle arrays. On the other hand, preferred orientation of ZnO was inhibited in the case of calcinations in 100% water vapor. A detailed thermal decomposition process of ZHC and the effect of water vapor on the crystal growth of ZnO are discussed.     

Intradiffusion coefficients for perchlorate ions in zinc perchlorate and zinc chloride solutions at 25°C: Comparing transport properties of zinc chloride and zinc perchlorate systems

Intradiffusion coefficients for³⁶ClO ₄ ^– have been measured in solutions of zinc perchlorate of concentration 0.1 to 3 mol dm^–3 at 25°C by the diaphragm cell technique. In addition, intradiffusion coefficients for perchlorate ions in zinc chloride solutions have been measured over a concentration range at 25°C. The results confirm previous work on the effect of complexation on diffusion in zinc chloride solutions above a salt concentration of 0.1M. The present data, together with literature data for diffusion coefficients of the other species present in the zinc perchlorate electrolyte system, have enabled a simple analysis of the hydration around the zinc ions to be carried out. This indicates that the water diffusion data are consistent with the zinc ions having an effective hydration sphere of 11 (±2) water molecules. This is in keeping with values obtained for other simple divalent electrolytes using the same model. The model is extended here to allow analysis of water diffusion in zinc chloride solutions taking into account the presence of complexed chloro-zinc species. The experimental data are consistent with the effective hydration of the chloro-zinc complexes being independent of the number of chloride ligands and equal to 18±3 over a concentration range of 0 tol mol-dm^–3. This postulate is discussed in terms of its consequences on the water ligand dynamics for the complex equilibria.