Review of the Current Synthesis and Properties of Energetic Pentazolate and Derivatives Thereof
Dominique R. Wozniak, Davin G. Piercey
Abstract
The latest member of the azole family, the pentazolate or cyclo-N5−, has received increased attention since its first mass-spectral detection by Christe et al. in 2002. As it is carbon- and hydrogen-free, the pentazolate anion can release large amounts of energy while simultaneously decomposing to environmentally friendly nitrogen gas. Due to these attractive qualities, cyclo-N5− and related compounds are essential in the advancement of high-energy-density materials (HEDMs) research. This review aims to provide a consolidated report on all research done on cyclo-N5−, with a focus on pentazoles as energetic materials and on their experimental synthesis. Included in this review are the following: ① the historical significance of cyclo-N5−; ② precursors of cyclo-N5−; ③ synthesis routes of cyclo-N5− with a focus on arylpentazole precursors; ④ factors affecting the stability of cyclo-N5−; ⑤ energetic performances of current energetic cyclo-N5−-containing compounds; and ⑥ future possible experimental research. This review is a comprehensive summary of the current understanding of cyclo-N5−, in an effort to further understand the potential of this anion for adoption as a powerful and environmentally friendly next-generation explosive.