Energetic Salts Based on Monoanions of N,N-Bis(1H-tetrazol-5-yl)amine and 5,5′-Bis(tetrazole)

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Abstract

High-density energetic salts that contain nitrogen-rich cations and the 5-(tetrazol-5-ylamino)tetrazolate (HBTA) or the 5-(tetrazol-5-yl)tetrazolate (HBT) anion were readily synthesized by the metathesis reactions of sulfate salts with barium compounds, such as bis[5-(tetrazol-5-ylamino)tetrazolate] (Ba(HBTA)2), barium iminobis(5-tetrazolate) (BaBTA), or barium 5,5′-bis(tetrazolate) (BaBT) in aqueous solution. All salts were fully characterized by IR spectroscopy, multinuclear (1H, 13C, 15N) NMR spectroscopy, elemental analyses, density, differential scanning calorimetry (DSC), and impact sensitivity. Ba(HBTA)24 H2O crystallizes in the triclinic space group Pequation image, as determined by single-crystal X-ray diffraction, with a density of 2.177 g cm−3. The densities of the other organic energetic salts range between 1.55 and 1.75 g cm−3 as measured by a gas pycnometer. The detonation pressure (P) values calculated for these salts range from 19.4 to 33.6 GPa, and the detonation velocities (νD) range from 7677 to 9487 m s−1, which make them competitive energetic materials. Solid-state 13C NMR spectroscopy was used as an effective technique to determine the structure of the products that were obtained from the metathesis reactions of biguanidinium sulfate with barium iminobis(5-tetrazolate) (BaBTA). Thus, the structure was determined as an HBTA salt by the comparison of its solid-state 13C NMR spectroscopy with those of ammonium 5-(tetrazol-5-ylamino)tetrazolate (AHBTA) and diammonium iminobis(5-tetrazolate) (A2BTA).

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