As a new type of polynitrogen species that is stable at room temperature, pentazolate anion (cyclo-N5−) has attracted much attention in the field of high-energy-density materials, but its energy and stability are unbalanced. Cocrystallisation can balance their properties to some extent by forming new chemical compositions from existing cyclo-N5− compounds through non-covalent interactions. This article reviews the research progress of cyclo-N5− cocrystals in recent years, including synthetic methods, cocrystals of metal-N5− compounds, and cocrystals of nonmetallic pentazolate salts. The cocrystals of metal-N5− compounds mainly includes metal-N5− solvates, cocrystals composed of metal-N5− compounds and amines/MSM, and metal containing composite salts; The cocrystals of nonmetallic pentazolate salts includes cocrystals composed of cyclo-N5− salts and solvents, cocrystals composed of cyclo-N5− salts and N-heterocyclic molecules, and non-metallic composite salts. The fascinating crystal structures (in some cases topological structures), stable forms, and physicochemical properties of representative cocrystals were highlighted. In addition, the future directions that need to be focused on in this field were pointed out, including the development of more preparation methods, especially those suitable for scaling up; higher precision calculation or testing of enthalpy of formation; improvement of their thermal stabilities; creation cocrystals of cyclo-N5− salts and high-density, high oxygen balance, high-energy oxidizer; and exploration of formation mechanism.

中文翻译：

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含能环-五唑酸盐共晶的合成和性质


五唑酸阴离子（cyclo-N5−）作为一种在室温下稳定的新型聚氮物种，在高能量密度材料领域备受关注，但其能量和稳定性并不平衡。共结晶可以通过非共价相互作用从现有的环 N5− 化合物形成新的化学成分，从而在一定程度上平衡它们的性质。本文综述了近年来环-N5−共晶的研究进展，包括合成方法、金属-N5−化合物的共晶和非金属五唑酸盐的共晶。金属-N5−化合物的共晶主要包括金属-N5−溶剂化物、金属-N5−化合物和胺/MSM组成的共晶以及含金属的复合盐;非金属五唑酸盐的共晶包括由环-N5−盐和溶剂组成的共晶，由环-N5−盐和N-杂环分子组成的共晶，以及非金属复合盐。突出了代表性共晶体的迷人晶体结构（在某些情况下是拓扑结构）、稳定形式和物理化学性质。此外，还指出了该领域需要关注的未来方向，包括开发更多的制备方法，特别是那些适合放大的方法;更高精度的计算或测试形成焓;提高它们的热稳定性;产生环 N5− 盐和高密度、高氧平衡、高能氧化剂的共晶体;以及探索形成机制。