2,5,2'-trichloro-1,1'-azo-1,3,4-triazole (1) was treated with sodium azide to afford a novel high nitrogen compound of polyazidotriazole involving a tetrazene (N—N＝N—N) structure: 2,5,2'-triazido-1,1'- azo-1,3,4-triazole (3). Under the same condition, 2,5,2',5'-tetraazido-1,1′-azo-1,3,4-triazole (b) was not accomplished, whereas its decomposed product 3,5-diazido-1,2,4- triazole (4) has been obtained in an acceptable yield. The crystal structures of 3 and 4 have been determined by X-ray diffraction analysis. The crystal measurement of 4 showed that the annular tautomerism phenomenon was due to the NH acidity and the intermolecular hydrogen bonds leading to a trimer with a 9-membered cycle.

Key words: high nitrogen compound, triazole, azido, crystal structure, synthesis