Sodium Azide NaN3 Research Articles

Stabilization of pentazolate anions in the high-pressure compounds Na2N5 and NaN5 and in the sodium pentazolate framework NaN5·N2.

Synthesis and characterization of nitrogen-rich materials is important for the design of novel high energy density materials due to extremely energetic low-order nitrogen-nitrogen bonds. The balance between the energy output and stability may be achieved if polynitrogen units are stabilized by resonance as in cyclo-N5- pentazolate salts. Here we demonstrate the synthesis of three oxygen-free pentazolate salts Na2N5, NaN5 and NaN5·N2 from sodium azide NaN3 and molecular nitrogen N2 at ∼50 GPa. NaN5·N2 is a metal-pentazolate framework (MPF) obtained via a self-templated synthesis method with nitrogen molecules being incorporated into the nanochannels of the MPF. Such self-assembled MPFs may be common in a variety of ionic pentazolate compounds. The formation of Na2N5 demonstrates that the cyclo-N5 group can accommodate more than one electron and indicates the great accessible compositional diversity of pentazolate salts.

First-principles studies of the electronic and magnetic structures and bonding properties of boron subnitride B13N2

Rhombohedral B12 unit is viewed as a host matrix embedding linear tri-atomic arrangements of elements (E) resulting in a relatively large family of boron-rich compounds with B12{E-E-E} generic formulation. The present work focuses on boron subnitride, B13N2 that we express in present context as B12{N–B–N}. Within well established quantum density functional theory (DFT) a full study of its electronic properties is provided.Also, in view of the existence of linear triatomic arrangements in simple compounds as sodium azide NaN3, i.e. NaI{N–N–N} and calcium cyanamide, CaII{N–C–N}, we devised ScIII{N–B–N} to establish comparison with B12{N–B–N}. ScBN2 is calculated to be cohesive and possessing N–B–N isolated from ScIII with dB-N ​= ​1.33 ​Å. In B12{N–B–N} an elongated dB-N ​= ​1.43 ​Å is identified due to the bonding of N with one of the two B12 boron substructures, B1 with the formation of “3B⋯N–B–N⋯3B“-like complex accompanied by a magnetic instability. Spin polarized (SP) calculations led to the onset of magnetization on central boron with M ​= ​1μB in a stable half-ferromagnetic ground state observed from the electronic density of states (DOS). The results are backed with total energy calculations in both non-spin-polarized (NSP) and spin-polarized stabilizing the latter configuration over a broad range of volumes from M(V) plots. Further illustrative results are given with the charge densities (total and magnetic) and electron localization function (ELF). Close observations (DOS) and results (crystal parameters and magnetization magnitude) were found from complementary calculations using Hartree-Fock exchange scheme.

Triazoles with long chain alkyl groups as a potential biological compounds

New series of four compounds was synthesized from multi hydroxyl group compounds such as methyl glycoside by coupling with long-chain alky propargyl ester ( C10, C12, C14 and unsaturated C18) via click chemistry after activation the hydroxyl at C6 position by chlorination with N-chlorosuccinimide NCS and functionalized with sodium azide NaN3. The chemical structures and the purity of the resulting triazoles derivatives was confirmed by elemental analysis (CHN) and spectroscopic analysis 1H NMR & 13C NMR. The biological activity for the target compounds was investigated, and they show good antibacterial and antifungal properties against some selected gram-posative and fungi, which make them suitable for medical applications.

Nitride nanopowders by azide SHS technology

Azide SHS technology with NaN3 powder as a nitriding agent was used to fabricate TiN–BN, AlN–BN, and Si3N4–TiN nanopowders using Nа2TiF6, (NH4)2TiF6, KBF4, NH4BF4, Nа3AlF6, AlF3, Na2SiF6, and (NH4)2SiF6 as precursors. Mixtures of the above salts with sodium azide NaN3 readily burned in an SHS reactor to yield agglomerated nanosized or fine target powders. Phase composition of combustion products not always corresponded to expectations and often contained insoluble byproducts. Reported are optimal green compositions and procedures that afford the preparation of target TiN–BN, AlN–BN, and Si3N4–TiN nanopowders free of byproducts.

Investigation of possibility to fabricate Si3N4-TiN ceramic nanocomposite powder by azide SHS method

The process of self-propagating high-temperature synthesis with use of a powder of sodium azide NaN3 as a nitriding agent (the SHS-Az method) was applied to fabricate a nanocomposite powder Si3N4-TiN. Combustion of the initial mixtures of NaN3 only with precursors that are halides of silicon and titanium: Na2SiF6, (NH4)2SiF6, Na2TiF6, (NH4)2TiF6 did not allow us to synthesize the composite powder of Si3N4-TiN, as the phases of silicon nitride Si3N4 were not formed. After water washing, the ultrafine powdered product of combustion consisted of one target phase of titanium nitride only and a large amount of impurity of side phases. Replacement of the halide salt of one of the elements (Si or Ti) by the powder of this element in the initial mixture of SHS-Az system resulted in formation of silicon nitride together with the titanium nitride and impurities. The least amount of impurities was obtained by burning the initial mixtures of xSi + y(NH4)2TiF6 + zNaN3 system. Only the initial mixture of 9Si + (NH4)2TiF6 + 6NaN3 allowed us to obtain as a result of the SHS-Az process the nanostructured composite powder of Si3N4-TiN without impurities.

Ca2Mg5GeN6 – A Layered Nitridomagnesogermanate

AbstractThe nitridomagnesogermanate Ca2Mg5GeN6 was synthesized at 780 °C using a sodium flux in sealed tantalum ampules. Pure metals were used as starting materials and sodium azide NaN3 was added as nitrogen source. Ca2Mg5GeN6 was obtained as a byproduct in the form of colorless platelet‐like crystals. Solution and refinement of the crystal structure [space group P63/mmc (no. 194), Z = 1, a = 3.453(2), c = 17.506(13) Å and V = 180.8(2) Å3] were performed on the basis of single‐crystal X‐ray diffraction data. Ca2Mg5GeN6 represents the first layered nitridogermanate. Its structure is made up of corner‐sharing (Mg/Ge)N4 tetrahedra and corner‐sharing trigonal planar (Mg/Ge)N3 units with mixed occupancy of Mg and Ge. Ca2+ ions are located in between the sheets. The crystal structure is closely related to that of the nitridomagnesoaluminate CaMg2AlN3 as well as to the carbides ScAl3C3 and UAl3C3.

Fabrication of Al-AlN Nanocomposites

A review of the methods of obtaining and properties of aluminum matrix composites, discretely reinforced with ceramic particles and nanoparticles of aluminum nitride AlN, is given. The survey shows that at low weight, nanocomposites Al-AlN possess improved physical and mechanical properties, including at high temperatures up to 400-550°C, which makes them very attractive for applications in automotive, aerospace and semiconductor technology. However, due to the long duration and energy consumption, expensive and complicated equipment, low productivity of existing solid-phase methods of powder metallurgy and liquid-phase metallurgical processes of fabrication of nanocomposites of Al-AlN, there are not yet the mastered technologies of industrial production of these composites. Azide technology of self-propagating high-temperature synthesis (SHS-AZ) using sodium azide NaN3 as a solid nitriding reagent allows you to get relatively inexpensive nanopowder of aluminum nitride in the form of nanofibers along with side salt of cryolite Na3AlF6, which can play the role of flux when working with molten aluminum. A new simple ex-situ method of introduction of AlN particles in the molten aluminum alloy in the form of a composite master alloy obtained by fusing together a flux carnallite KCl·MgCl2 with AlN nanopowder mixed with cryolite Na3AlF6 was proposed. Results of experiments on the application of the proposed method for obtaining nanocomposite with matrix made of aluminum-magnesium alloy AlMg6 containing up to 1 % of the reinforcing phase AlN are presented.

APPLICATION OF THE NANOPOWDER PRODUCTION OF AZIDE SHS TECHNOLOGY FOR THE REINFORCEMENT AND MODIFICATION OF ALUMINUM ALLOYS

The survey of types and fabrication methods of aluminum matrix composite materials discretely reinforced with ceramic particles and nanoparticles of refractory compounds is given. It is shown that the azide technology of self-propagating high-temperature synthesis (SHS-Az), which uses sodium azide NaN3 as a solid nitriding agent, makes it possible to fabricate numerous comparatively inexpensive micropowders and nanopowders of nitrides, carbonitrides, carbides, and their compositions, which are of interest for the reinforcement and modification of aluminum alloy. Along with the mentioned target ceramic particles, the SHS-Az product contains side haloid salts (sodium and potassium chlorides and fluorides), which can play the role of fluxes with the addition of ceramic particles into the aluminum melt. The results of experiments on the introduction of the nanopowder composition into the melt of AK6M2 alloy, %: β -SiC – 48,6, α -Si3N4 – 27,0, β -Si3N4 – 5,8, Na3AlF6 – 18,6 in the composition of the compacted pseudo-master alloy with the copper powder, which evidence the modifying effect, are presented.

Application of the nanopowder production of azide SHS technology for the reinforcement and modification of aluminum alloys

The survey for types and fabrication methods of aluminum matrix composite materials discretely reinforced with ceramic particles and nanoparticles of refractory compounds is given. It is shown that the azide technology of self-propagating high-temperature synthesis (SHS-Az), which uses sodium azide NaN3 as a solid nitriding agent, makes it possible to fabricate numerous comparatively inexpensive micropowders and nanopowders of nitrides, carbonitrides, carbides, and their compositions, which are of interest for the reinforcement and modification of aluminum alloy. Along with the mentioned target ceramic particles, the SHS-Az product contains side haloid salts (sodium and potassium chlorides and fluorides), which can play the role of fluxes with the addition of ceramic particles into the aluminum melt. The results of experiments on the introduction of the nanopowder composition into the melt of AK6M2 alloy, %, β-SiC 48.6, α-Si3N4 27.0, β-Si3N4 5.8, and Na3AlF6 18.6 in the composition of the compacted pseudo-master alloy with the copper powder, which evidence the modifying effect, are presented.

天然海水中NaN 3 对316L不锈钢表面微生物膜催化阴极氧还原的影响

利用荧光显微观察技术选择临界使用浓度的NaN3,分别在O2及N2气氛下采用循环伏安及电化学阻抗技术研究其氧还原过程的电化学行为。结果表明,不锈钢表面的生物膜能够加大还原峰电流密度值,当使用临界浓度的NaN3处理不锈钢试样后,还原峰值明显减小,且峰电位均负移。微生物膜能够促进电子传递给最终电子受体O2,同时降低不锈钢材料发生腐蚀的可能性。由此推测,天然海水中,316L不锈钢表面微生物膜改变了传统阴极氧还原的电子传递途径,即加速了O2作为最终电子受体的电子传递过程,催化了O2的还原;同时,还能够抑制不锈钢材料的腐蚀。

Flash photolysis and pulse radiolysis studies on elastin hydrolysates

The formation of reactive species and free radicals in water soluble elastin hydrolysates have been investigated by pulse radiolysis and flash photolysis. Elastin hydrolysates were obtained by hydrolysis of elastin extracted from aorta.An investigation of the photochemical properties of elastin hydrolysates in water was carried out using nanosecond laser irradiation. The transient spectra of elastin hydrolysates solution excited at 266nm showed two bands. One of them with maximum at 295nm and the second one with maximum at 400nm.The reactions of hydrated electrons and OH radicals with elastin have been studied by pulse radiolysis. In the absorption spectra of products resulting from the reaction of elastin with eaq- small maximum absorption in UV and visible light was observed. In the absorption spectra of products resulting from the reaction of the hydroxyl radicals with elastin two bands were observed. The first one at 320nm and the second one at 410nm. Reaction of OH radicals with elastin hydrolysates lead to formation of Tyr phenoxyl radicals with absorption at 410nm. The influence of the addition of sodium azide NaN3 on the formation of the transients was evaluated.

Magnetic and structural characterization of superconducting sodium-doped C60 prepared with the thermal decomposition of sodium azide

Abstract We have prepared Na4C60 samples by the different ways of the thermal decomposition of sodium azide NaN3. The superconducting (SC) samples were obtained by the decomposition under the dynamic vacuum, while the non-SC samples by the decomposition in the sealed tube. The SC sample was composed of two fee phases with a lattice constant a=14.207(5)A (phase A) and a=14.339(4)A (phase B). On the contrary, the non-SC sample had single fee phase which can be assigned to phase A. This result strongly suggests that phase B is the SC phase.

Production of free sodium atoms for the spectrum-line reversal technique.

T^OR experimentally investigating the vibrational tempera-Iture of a gas, shock tubes and the spectrum-line reversal technique have been widely used. The shock tube produces the nonequilibrium conditions, and the spectrum-line reversal technique measures the vibrational temperature of the gas as a function of time. The reversal technique commonly relies on the introduction of the reversal atoms into the gas in the form of a compound. Typical compounds are sodium chloride, sodium iodide, and chromium carbonyl. These metallic compounds are decomposed by the high-temperature gas behind the incident shock wave in the shock tube. Experimental evidence strongly suggests that the excited metallic atoms follow the vibrational temperature of the gas. The validity of the experimental technique is not discussed here. The purpose of this Note is to show how some of the difficulties arising from the use of the aforementioned compounds may be avoided by introducing metallic atoms into the gas by the use of sodium azide NaN3.