Quadruple azidation of 2,4,6,8-tetrachloropyrimido[5,4-d]pyrimidine gave tetraazidopyrimido[5,4-d]pyrimidine (C₆N₁₆) with 86% yield. The title compound undergoes azide–tetrazole tautomerism in neutral organic solvents, but exists as a protonated C₂-symmetric tetraazide dication in trifluoroacetic acid. On the other hand, in the solid state it occurs as a monotetrazole tautomer as revealed by its single crystal X-ray analysis. The newly obtained binary compound C₆N₁₆ is very sensitive towards both impact (<1 J) and friction (1 N). A detonation velocity of 7477 m s⁻¹ with a 20.8 GPa detonation pressure was calculated using the EXPLO5 code (version V7.01.01).

中文翻译：

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2,4,6,8-四叠氮嘧啶并[5,4-d]嘧啶：一种新型含能二元化合物

2,4,6,8-四氯嘧啶并[5,4- d ]嘧啶的四重叠氮化得到四叠氮嘧啶并[5,4- d ]嘧啶(C ₆ N ₁₆ )，产率86%。标题化合物在中性有机溶剂中发生叠氮-四唑互变异构，但在三氟乙酸中以质子化的C _{2 -对称四叠氮二价形式存在。}另一方面，单晶 X 射线分析显示，在固态时，它以单四唑互变异构体的形式出现。新获得的二元化合物C ₆ N ₁₆对冲击（<1 J）和摩擦（1 N）都非常敏感。爆速为 7477 ms ^-1使用 EXPLO5 代码（版本 V7.01.01）计算出 20.8 GPa 的爆炸压力。