Investigation of Intramolecular Interactions in the Crystals of Tetrazene Explosive and Its Salts

Abstract

This work presents the reinvestigation of 5-[(1E)-3-amidiniotetraz-1-en-1-yl]­tetrazolide hydrate (tetrazene) explosive. Quantum-chemical calculations have been performed to estimate the relative energies of the structural isomers of tetrazene. Five salts of tetrazene have been prepared by its reactions with mineral acids. A high-resolution X-ray diffraction study in 1-amino-1-[(1H-tetrazol-5-yl)­azo]­guanidinium bromide crystals and electron-density topology analysis have been carried out. Both experimental and theoretical comparisons of all compounds, based on the number and strength of intermolecular contacts, show a strong influence of the solvate and the nature of the anion present in the supramolecular architecture of the compounds. The impact and friction sensitivity for tetrazene and its salts have been determined as well.

Tetrazene–Characterization of Its Polymorphs

“…While Duke identified his forms A and B within space groups P2 1 /a and Ia , respectively, we unambiguously found a form within space group Cc with unit cell parameters of a = 12.0461 Å, b = 9.3264 Å, c = 6.7419 Å, and β = 98.835° (measured at 150 K) [ 4 ]. These particular unit cell parameters and space group are found in whole temperature range of 150–293 K with only negligible changes and no phase transformation, as confirmed also by DSC measurements (more Section 2.1.4 ).…”

“…For this reason, we decided to label our only slightly different form, of which we obtained a single crystal, as form C [ 4 ] in order to avoid further confusion between these forms, given their similarities. Unfortunately, A and B form single crystals were not obtained.…”

“…The measured powder pattern of bulk tetrazene C (preparation details described in Section 3.1 ) has been compared with a calculated pattern using single crystal structure data of only recently reported form C [ 4 ]. The sample of tetrazene C contains only form C. All measured diffraction peaks were indexed and are consistent with the Cc space group ( Figure 3 a).…”

“…Tetrazene (5-[(1 E )-3-amidiniotetraz-1-en-1-yl]tetrazolide hydrate, known also under different names such as 1-amino-1-[(l H -tetrazol-5-yl)azo]guanidine hydrate and 1-amino-1-(tetrazol-5-yldiazenyl)guanidin monohydrate [ 4 ]) is one of the most industrially produced and used primary explosives ( Figure 1 ). It is used as an energetic sensitizer in many initiating compositions, particularly in percussion and stab priming mixtures [ 2 , 5 , 6 ] used for the ignition of the powder charge in cartridges and initiation devices in other munitions products.…”