Specific Features Of Synthesis Research Articles

Oximes of fluoroalkyl-containing 1,3-diketones: specific features of synthesis, analysis, and thermal stability

Oximes of fluoroalkyl-containing 1,3-diketones: specific features of synthesis, analysis, and thermal stability

Specific Features of Synthesis, Structure, Magnetometry, and NMR Spectroscopy of Different-Type Nanowires

Specific Features of Synthesis, Structure, Magnetometry, and NMR Spectroscopy of Different-Type Nanowires

Specific features of synthesis and luminescence for lithium–aluminum spinels doped with manganese ions

Ceramic samples of lithium aluminates doped with manganese ions have been synthesized by a solid-state reaction method. The ceramics sintered at temperatures of 1000, 1100, 1200 or 1300 °C for 4 h in air are identified as LiAl5O8 compounds belonging to a spinel-like crystal structure with the P4132 space group. Nonetheless, ceramic compositions obtained by annealing at temperatures 1000, 1100 or 1200 °C have larger lattice parameters than that of a LiAl5O8 single crystal and are considered as metastable LiAl5O8 phases having partial disorder for the occupation of two inequivalent octahedral sites by Li+ and Al3+ ions, i.e. possessing Li - Al inversion. Such Mn doped disordered compositions show typical Mn4+ red luminescence with an emission peak at ∼662 nm. The charge compensation of Mn4+ replacing Al3+ ions in octahedral sites is achieved by Li+ ions entering some adjacent Al3+ sites due to inversion. On the other hand, annealing at a higher temperature (1300 °C) or prolonged (170 h) annealing at a lower temperature (1100 °C) leads to complete ordering of Li+ and Al3+ in ratio 1:3 at different octahedral sites in the LiAl5O8 structure in which Mn4+ luminescence is not observed due to the lack of a charge compensation mechanism. Doping Mn ions in such an ordered structure are realized in di- and trivalent states causing green and far-red luminescence, respectively. Additional annealing of the mixtures of the Mn-doped ordered LiAl5O8 composition and Li2CO3 at 1300 °C in air results in the production of phosphors which again show intense Mn4+ red luminescence and have the spinel-like crystal structure with the Fd3‾m space group due to random occupation of cationic sites by Li+ and Al3+ ions.

Specific Features of Synthesis and Luminescence for Lithium Aluminum Spinel LiAl5O8 Doped with Manganese Ions

Specific Features of Synthesis and Luminescence for Lithium Aluminum Spinel LiAl5O8 Doped with Manganese Ions

Composite electrode material based on cobalt-vanadium oxide CoV3O8 and oxide compounds of molybdenum

Specific features of synthesis and capacity for reversible electrochemical intercalation of lithium were studied for the electrode composite material on a carbon support, based on cobalt-vanadium oxide and oxide molybdenum compounds deposited from aqueous solutions of their salts under polarization with an alternating asymmetric current.

Synthesis and phase transitions of oxide-ion conducting compound La2Mo2O9 doped with alkaline metals

The specific features of synthesis, polymorthism, and electric conductivity of oxide-ion conducting compounds La2 − x Me x Mo2O9 − y , where Me = Na, K, Rb, or Cs, have been studied. Ceramic samples were obtained by solid-state synthesis in the temperature range of 960–1100°C. The regions where solid solutions exist have been found to depend on the temperature of the sample firing. According to the calorimetric and electrophysical data, the phase transition from the monoclinic phase (α) to the cubic phase (β) in samples doped with potassium and rubidium disappears at x = 0.02 and 0.04, respectively. In these cases the only transition from the cubic β ms phase to the high-temperature cubic β phase is observed near 450°C. Doping with sodium and cesium does not suppress the α → β phase transition.

10.1007/s11498-008-2009-8

The specific features of synthesis of poly(methyl methacrylate) and polystyrene in the presence of bis(3,6-ditert-butylcatecholato)tin(IV) ditetrahydrofuranate were studied. It was found that the catecholate tin complex can efficiently influence both the kinetic parameters of radical polymerization of the monomers and molecular mass characteristics of the product polymers. With the use on macroinitiators obtained in the presence of bis(3,6-ditert-butylcatecholato)tin(IV) ditetrahydrofuranate, block copolymers were synthesized.

Specific features of synthesis, chemical composition, and thermal stability of anodic borosilicate coatings on silicon

Thickness and resistivity of anodic borosilicate coatings synthesized on n-type silicon were studied in relation to the conditions in which the final forming potentials are reached and to the content of boric acid in an ethylene glycol solution. A method for synthesis of the coatings for use in nanoelectronics was suggested on the basis of data on the thermal stability of their chemical composition.