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V = N, P, As, Sb)
Published in Vasyl Tomashyk, Multinary Alloys Based on III-V Semiconductors, 2018
The Ag(Sb7Te8)[GaCl4] quinary compound, which exists in two polymorphic modifications, is formed in the Ga–Ag–Te–Cl–Sb system (Eich et al. 2014). Both modifications crystallize in the triclinic structure with the lattice parameters a = 1,829.76 ± 0.03, b = 1,278.06 ± 0.02, and c = 2,690.53 ± 0.04 pm and α = 125.37 ± 0.01°, β = 132.06 ± 0.01°, and γ = 91.75 ± 0.01 and a calculated density of 3.92 g cm−3 at 123 K for α-modification and a = 1,834.21 ± 0.07, b = 1,278.15 ± 0.04, and c = 1,352.12 ± 0.05 pm and α = 125.38 ± 0.01°, β = 132.23 ± 0.01°, and γ = 91.58 ± 0.01 and a calculated density of 3.90 g cm−3 at 163 K for β-modification. To synthesize this compound, Te (0.36 mM), Sb (0.24 mM), SbCl3 (0.12 mM), GaCl3 (0.99 mM), AgCl (0.18 mM), and tetraphenylphosphonium chloride (0.16 mM) were placed in a glass ampoule under an Ar atmosphere. The ampoule was evacuated and flame-sealed. After 19 days at 100°C, black rod-shaped crystals with metallic shiny surfaces appeared in a liquid black melt. The actual orange color of the crystals was revealed as they were ground to a powder. The title compound is air sensitive.
Systems Based on GaSb
Published in Vasyl Tomashyk, Quaternary Alloys Based on III-V Semiconductors, 2018
(Sb3Te4)[GaCl4] crystallizes in the monoclinic structure with the lattice parameters a = 1445.1 ± 0.2, b = 419.58 ± 0.04, c = 1289.9 ± 0.1 pm, and β = 111.797 ± 0.004° (Eich et al. 2015). The title compound was prepared by the next procedure. Te (0.36 mM), Sb (0.24 mM), SbCl3 (0.12 mM), GaCl3 (0.99 mM), and tetraphenylphosphonium chloride (0.16 mM) were filled in a glass ampoule, which was evacuated and sealed. On annealing at temperatures between 50°C and 140°C, crystals appeared within 13 weeks in the form of silvery, metallic shiny rods. Tetraphenylphosphonium chloride may be replaced by NaCl. At slightly higher reaction temperatures between 130°C and 160°C, crystallization starts after 3 days. (Sb3Te4)[GaCl4] is highly moisture sensitive. Tube furnace used for synthesis of this compound was aligned at an angle of about 30° to the horizontal to keep the melt compacted in the hot zone.
Synthetic Methods for High-Energy Organofluorine Compounds
Published in Mark J. Mezger, Kay J. Tindle, Michelle Pantoya, Lori J. Groven, Dilhan M. Kalyon, Energetic Materials, 2017
Haiges and Christe have synthesized 5-(fluorodinitromethyl)-2H-tetrazole (98) by the cycloaddition of 2-fluoro-2,2-dinitroacetonitrile (97) with hydrazoic acid (HN3), and a series of the corresponding tetrazolate salts were synthesized through acid-base reactions of the tetrazole 98.38 The reaction of the tetrazole 98 with aqueous ammonia gave the corresponding ammonium tetrazolate salt 99, whereas reaction of 98 with AgNO3 and tetraphenylphosphonium chloride gave the corresponding tetrazolate salts 100, and 101, respectively (Figure 1.21). Some of the tetrazolate derivatives, such as the phosphonium salt 101, have substantially higher frictional impact sensitivity values (i.e., they are substantially more stable than the RDX) and have comparable thermal stabilities as that of RDX (Figure 1.21).
Bis phenylene flattened 13-membered tetraamide macrocyclic ligand (TAML) for square planar cobalt(III)*
Published in Journal of Coordination Chemistry, 2018
W. Chadwick Ellis, Alexander D. Ryabov, Andreas Fischer, Joshua A. Hayden, Longzhu Q. Shen, Emile L. Bominaar, Michael P. Hendrich, Terrence J. Collins
Macrocycle 10 (50 mg, 0.136 mmol) was placed into a 50 mL dried round bottom flask under argon. Distilled THF (25 mL) was added. Lithium bis(trimethylsilyl) amide (0.2 mL, 1 M in THF, 0.2 mmol) was added (0.367 eq relative to amide protons). Vanadium(V) triisopropoxide oxide (40 mg, 0.164 mmol) was added and stirred. After 24 h, the reaction mixture was poured into 100 mL heptane, and over the course of a few hours, a green solid precipitate formed on the walls of the beaker as heptane evaporated. This was collected (approximately 5 mg), dissolved in water, precipitated with tetraphenylphosphonium chloride, and collected by filtration on filter paper. The precipitate was then dissolved in 2 mL MeCN and 1.5 mL water was added. This mixture was heated at 70 °C in a water bath until approximately 0.5 mL of solvent evaporated, and then left to stand for 2 weeks at room temperature. Small yellow/green crystals that formed were studied by X-ray crystallography [28].
Effect of HEH[EHP] impurities on the ALSEP solvent extraction process
Published in Solvent Extraction and Ion Exchange, 2018
Vanessa E Holfeltz, Emily L. Campbell, Dean R. Peterman, Robert F. Standaert, Alena Paulenova, Gregg J. Lumetta, Tatiana G Levitskaia
31P NMR measurements were performed on a Varian VNMRS spectrometer operating at a field strength of 17.6 T (1H ν0 = 748.4 MHz, 31P ν0 = 303.0 MHz) with a Varian 5 mm direct, broadband tuneable, pulsed-field gradient (PFG) probe. The temperature was regulated at 25°C for all experiments. Unless otherwise specified, each spectrum was acquired using a 90° pulse width of 13.375 µs, an acquisition time of 0.89 s, and a recycle delay of 30 s. The number of transients collected varied from 64 to 256. Broadband 1H decoupling employing the WALTZ-16 composite pulse scheme was applied during acquisition only. The resulting free induction decays were zero-filled to 64k points and multiplied by an exponential decay function to give 1 Hz line broadening. Spectra were referenced to zero ppm using an external reference of 85% phosphoric acid. For quantitative studies, spectra were referenced using the 31P signal of 50 mM tetraphenylphosphonium chloride in CDCl3 contained in a coaxial insert. Processing was performed using VNMRJ 4.0 and Mestrenova 10.0.