Takehiro Matsunaga

Crystal structure of anhydrous 5-aminotetrazole and its high-pressure behavior

Anhydrous 5-aminotetrazole (5-amino-1H-tetrazole, 5-ATZ) is an energetic material that produces a large amount of nitrogen gas by thermal decomposition and is often used as a gas generator agent. Although it is used widely as an air bag inflator, its crystal structure has not been determined yet. Thus, we performed a powder X-ray diffraction experiment, a Rietveld analysis, and the density functional theory calculation to investigate its structure and determined it to be an orthorhombic P212121 with a 1H-form molecule. We also investigated the high-pressure behavior and found that the orthorhombic phase is stable up to at least 11.6 GPa. Furthermore, the quantum molecular dynamics calculations at high-temperature and high-pressure of 5-ATZ were carried out and predicted the phase change including molecular decomposition.

5-Methyl-1H-tetrazole

We have determined the molecular structure of the title compound, C 2 H 4 N 4 , using X-ray crystallography. The tetrazole ring is expected to be an aromatic system. The ring stricture is not very different from that of 1-methyl-tetrazole. The C-C bond length is shorter than expected and this indicates that the electron of the tetrazole ring expands to the methyl group.

Hexaaquairon(II) dipicrate dihydrate.

In the crystal structure of the title compound, [Fe(H(2)O)(6)](C(6)H(2)N(3)O(7))(2).2H(2)O, the centrosymmetric cationic iron complexes and picrate anions form separate stacks extending along the b axis. No picrate species ligate to the metal cation. Picrate ions are linked to one another in the stack via short intermolecular C.C contacts of 3.083 (4) and 3.055 (4) A. Variable-temperature X-ray diffraction measurements performed between room temperature and 93 K showed a linear decrease of the lattice parameters, suggesting that there is no phase transition.

1H-Tetrazol-5(4H)-one

The molecular structure determination of the title compound, CH 2 N 4 O, determined by X-ray crystallography reveals it to be 1H-tetrazol-5(4H)-one, not 5-hydroxytetrazole which had been generally accepted; 1H-tetrazol-5(4H)-one is the keto form with C 2v symmetry. Ab initio calculations at the MP2/6-31G * level also indicate that 1H-tetrazol-5(4H)-one is the most stable tautomer.

Analysis of an explosion accident of nitrogen trichloride in a waste liquid containing ammonium ion and platinum black

Five liters of sodium hypochlorite aqueous solution (12 mass%) was poured into 300 L of liquid waste containing ammonium ion of about 1.8 mol/L in a 500 L tank in a plant area; then, two minutes later the solution exploded with a flash on March 30th, 2005. The tank cover, the fluorescent lamp and the air duct were broken by the blast wave. Thus, we have conducted 40 runs of laboratory-scale explosion tests under various conditions (solution concentrations of (NH4)2SO4 and NaClO, temperatures, Pt catalysts, pH, etc.) to investigate the causes for such an explosion. When solutions of ammonium sulfate and sodium hypochlorite are mixed in the presence of platinum black, explosions result. This is ascribable to the formation of explosive nitrogen trichloride (NCl3). In the case where it is necessary to mix these 2 solutions (ammonium sulfate and sodium hypochlorite) in the presence of platinum black, the following conditions would reduce a probability of explosion; the initial concentration of NH4(+) should be less than 3 mol/L and the pH should be higher than 6. The hypochlorite solution (in 1/10 in volume) to be added at room temperature is recommended to be less than 0.6 mol/L.

A basic test method for the study of explosion treatment of waste chemicals from laboratories

As a part of the research on the explosion treatment of waste chemicals from laboratories, a basic test method, which will provide the basis for our future research, was developed. First, the basic explosive, the scale of the explosion chamber and the assembly of the sample were decided. Then, measurement of detonation velocity was carried out, and the relationship between the quantity of explosive and the state of detonation propagation was obtained. A quantitative method for evaluating the decomposability of organic chemicals under explosion treatment was investigated. The results indicate that evaluating the explosion decomposability of organic chemicals from the gasification ratio could be used as a basic method provided that the excessive oxygen is approximately 62 mol% or higher. Finally, examinations of the possible effects of the quantity of explosive and conditions of atmosphere on the explosion decomposition of the model substance were conducted, and the basic test conditions regarding the quantity of explosive and condition of atmosphere were decided.

Hexaaquazinc(II) dipicrate trihydrate.

In the crystal structure of the title compound, [Zn(H2O)6](C(6)H(2)N(3)O(7))2.3H2O, the zinc cation complexes and picrate anions are stacked separately, extending along the b axis. No picrate species ligate to the metal cation. This lack of picrate coordination is atypical among metal picrate salts. We speculate that the size of the metal-aqua complex as related to the intermolecular distance of the picrate anions in the pi stack can be a measure of the formation of such separated stacks in the crystal structures of divalent metal complexes with picrate anions. Picrate ions are linked to each other with short intermolecular C...C contacts of 3.223 (6) and 3.194 (6) A in the stack.

Soil cratering by surface explosions of cylindrical TNT charges

The objective of this paper is to present an empirical equation that can express the crater dimensions achieved by surface TNT explosions as a function of charge weight, height-of-burst, and geological material, as determined in field experiments on the safety of explosives that were conducted by MITI.

Equilibrium calculations of firework mixtures

Thermochemical equilibrium calculations have been used to calculate detonation conditions for typical firework components including three report charges, two display charges, and black powder which is used as a fuse or launch charge. Calculations were performed with a modified version of the TIGER code which allows calculations with 900 gaseous and 600 condensed product species at high pressure. The detonation calculations presented in this paper are thought to be the first report on the theoretical study of firework detonation. Measured velocities for two report charges are available and compare favorably to predicted detonation velocities. However, the measured velocities may not be true detonation velocities. Fast deflagration rather than an ideal detonation occurs when reactants contain significant amounts of slow reacting constituents such as aluminum or titanium. Despite such uncertainties in reacting pyrotechnics, the detonation calculations do show the complex nature of condensed phase formation at elevated pressures and give an upper bound for measured velocities.