Crystal structure of the 1:1 cocrystal 5,5′-(triaz-1-ene-1,3-diyl)bis(3-nitro-1H-1,2,4-triazole)–triethylammonium nitrate

Abstract

The triethylammonium nitrate cocrystal of 5,5′-(triaz-1-ene-1,3-diyl)bis(3-nitro-1H-1,2,4-triazole), C4H3N11O4·C6H16N·NO3 (3), was obtained unintentionally as the product of an attempted synthesis of a heterocyclic C-bromonitrilimine from 3-amino-5-nitro-1,2,4-triazole (ANTA). In the solid state at 150 K, the structure of 3 is modulated by a pseudo-translation along [010] with Z* = 4 (Z = 8 in P1). Exact translational symmetry is broken by a slight modulation of the triazene molecules and nitrate anions, and by disorder of two of the four triethylammonium cations. An extensive hydrogen-bonding network connects the components of the structure and enables a relatively high density of 1.516 g cm−3. This feature, as well as its high nitrogen content, make this rare triazene-bridged 1,2,4-triazole and possible related similar compounds of interest as potential energetic materials.

Keywords

• crystal structure
• 1,2,4-triazole
• energetic material
• hydrogen bonding
• x-ray crystallography
• high z*
• pseudosymmetry