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Updated: Jul 31, 2026
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Effect of counter-ion on packing and crystal density of
Ian D Giles1, Alan J DeHope2, Nathaniel B Zuckerman2
1CBMSE, Code 6910, Naval Research Laboratory, Washington, DC 20375, USA.
Abstract:
In energetic materials, the crystal density is an important parameter that affects the performance of the material. When making ionic energetic materials, the choice of counter-ion can have detrimental or beneficial effects on the packing, and therefore the density, of the resulting energetic crystal. Presented herein are a series of five ionic energetic crystals, all containing the dianion 5,5'-(3,3'-bi[1,2,4-oxa-diazole]-5,5'-di-yl)bis-(1H-tetra-zol-1-olate), with the following cations: hydrazinium (1) (2N2H5+·C6N12O42-), hydroxyl-ammonium (2) 2NH4O+·C6N12O42- [Pagoria et al.. (2017). Chem. Heterocycl. Compd, 53, 760-778; included for comparison], di-methyl-ammonium (3) (2C2H8N+·C6N12O42-), 5-amino-1H-tetra-zol-4-ium (4) (2CH4N5+·C6N12O42-·4H2O), and amino-guanidinium (5) (2CH7N4+·C6N12O42-). Both the supra-molecular inter-actions and the sterics of the cation play a role in the density of the resulting crystals, which range from 1.544 to 1.873 Mg m-1. In 5, the tetra-zolate ring is disordered over two positions [occupancy ratio 0.907 (5):0.093 (5)] due to a 180° rotation in the terminal tetra-zole rings.
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