Structural stability, vibrational, and bonding properties of potassium 1, 1′-dinitroamino-5, 5′-bistetrazolate: An emerging green primary explosive

Abstract

Potassium 1,1′-dinitroamino-5,5′-bistetrazolate (K2DNABT) is a nitrogen rich (50.3% by weight, K2C2N12O4) green primary explosive with high performance characteristics, namely, velocity of detonation (D = 8.33 km/s), detonation pressure (P = 31.7 GPa), and fast initiating power to replace existing toxic primaries. In the present work, we report density functional theory (DFT) calculations on structural, equation of state, vibrational spectra, electronic structure, and absorption spectra of K2DNABT. We have discussed the influence of weak dispersive interactions on structural and vibrational properties through the DFT-D2 method. We find anisotropic compressibility behavior (b<a<c) from pressure dependent structural properties. The predicted equilibrium bulk modulus reveals that K2DNABT is softer than toxic lead azide and harder than the most sensitive cyanuric triazide. A complete assignment of all the vibrational modes has been made and compared with the available experimental results. The calculated zone center IR and Raman frequencies show a blue-shift which leads to a hardening of the lattice upon compression. In addition, we have also calculated the electronic structure and absorption spectra using recently developed Tran Blaha-modified Becke Johnson potential. It is found that K2DNABT is a direct band gap insulator with a band gap of 3.87 eV and the top of the valence band is mainly dominated by 2p-states of oxygen and nitrogen atoms. K2DNABT exhibits mixed ionic (between potassium and tetrazolate ions) and covalent character within tetrazolate molecule. The presence of ionic bonding suggests that the investigated compound is relatively stable and insensitive than covalent primaries. From the calculated absorption spectra, the material is found to decompose under ultra-violet light irradiation.

Structure–Property Correlation Studies of Potassium 4,4′-Bis(dinitromethyl)-3,3′-azofurazanate: A Noncentrosymmetric Primary Explosive

“…In order to know their intensity differences for analyzing the structure–polarization relation, we have calculated the IR spectra of K 2 BDAF material and plotted this in Figure . The results are compared with its isostructural crystal K 2 DNABT results reported in ref . The top portion of Figure (total IR spectra) shows that both the K 2 BDAF and K 2 DNABT explosives have unique/different vibrational spectra.…”

“…Calculated IR spectra of K 2 BDAF and K 2 DNABT crystal structures optimized at the G06 level. Here, the IR spectra of K 2 DNABT is recalculated as reported in ref and plotted on top of K 2 BDAF IR spectra for analysis purposes.…”

“…We report a in-depth study of structural, mechanical, vibrational properties, phonon dispersion studies, Born effective charge analysis, electronic band structure, and linear functions (complex dielectric function, absorption, refractive index, birefringence) of these primary explosives which have not been well reported until today. In the case of K 2 DNABT, we have utilized the previously reported data in ref for comparison purposes. We have illustrated the importance of noncentrosymmetry of these explosive materials and explained the detection limit and sensitivity differences within a wide spectral frequencies range.…”

Design and selection of triazole-based compounds with high energetic properties and stabilities

“…where, M is molecular mass in g•molecule −1 and V (0.001) is volume in cm 3 • molecule −1 , which is encompassed by the 0.001 e•Bohr −3 contour of the molecule's electronic density; α, β and γ are the regression coefficients; ν is a measure of the degree of balance between positive potential and negative potential on the isosurface, and σ 2 tot describes the variability of electronic potential on molecular surface.…”

Novel Energetic Coordination Polymers Based on 1,5-Di(nitramino)tetrazole With High Oxygen Content and Outstanding Properties: Syntheses, Crystal Structures, and Detonation Properties

“…Potassium-based energetic coordination polymers are considered to be promising “green” replacements of lead-based primary explosives. Recently, several new energetic coordination polymers as promising primary explosives based on furazano and tetrazolo energetic ligands, such as potassium 3-nitramino-4-tetrazolefurazanate (K 2 NATF) (Li Y. et al, 2017), potassium 3,6-bis(4-nitramino-1,2,5-oxadiazol-3-yl)-1,2,4,5-dioxadiazinate (K 2 BNAFD) (Li Y. et al, 2017), potassium 3,4-bis(3-dinitromethylfurazan-4-oxy)furazanate (K 2 BDFOF) (Zhai et al, 2015; Li Y. et al, 2017), potassium 4,4′-bis(dinitromethyl)-3,3′-azofurazanate (K 2 BDNMAF) (Tang et al, 2016), potassium 3-dinitromethyl-4-nitraminofurazanate (K 2 DNMNAF) (Li Y. N. et al, 2017), potassium 3,4-dinitraminofurazanate (K 2 DNAF) (Li Y. et al, 2017) and potassium 4,5-bis(dinitromethyl)furoxanate (K 2 BDNMF) (He and Shreeve, 2016), potassium 1,1′-dinitramino-5,5′-bistetrazolate (K 2 DNABT) (Fischer et al, 2014; Yedukondalu and Vaitheeswaran, 2015), and potassium 1,1′-dinitramino-5,5′-azobitetrazole (K 2 ABNAT) (Fischer et al, 2016; Li Y. N. et al, 2017) were reported (Scheme 1). However, most of the above-reported coordination polymers do not own excellent detonation properties and have negative oxygen balances (OBs).…”