▁but ▁compar atively ▁stable ▁chemical ▁comp ound ▁which ▁contains ▁a ▁long ▁continuous ▁chain ▁of ▁nit ro gen ▁atoms , ▁with ▁an ▁un bro ken ▁chain ▁of ▁eight ▁nit ro gen ▁atoms ▁cycl ised ▁into ▁two ▁ 1 , 2 , 3 - tri az ole ▁rings . ▁It ▁is ▁stable ▁up ▁to ▁ 1 9 4   ° C . ▁The ▁comp ound ▁exhib its ▁c is – trans ▁is omer ism ▁at ▁the ▁central ▁a zo ▁group : ▁the ▁trans ▁is omer ▁is ▁more ▁stable ▁and ▁is ▁yellow , ▁while ▁the ▁c is ▁is omer ▁is ▁less ▁stable ▁and ▁is ▁blue . ▁The ▁two ▁rings ▁are ▁a rom atic ▁and ▁form ▁a ▁conjug ated ▁system ▁with ▁the ▁a zo ▁link age . ▁This ▁chrom oph ore ▁allows ▁the ▁trans ▁comp ound ▁to ▁be ▁is omer ised ▁to ▁the ▁c is ▁when ▁treated ▁with ▁an ▁appropriate ▁w avel ength ▁of ▁ult rav io let ▁light . ▁ ▁Rel ated ▁comp ounds ▁In ▁ 2 0 1 1 , ▁az ob is ( t et raz ole ) ▁was ▁prepared ▁by ▁K lap öt ke ▁and ▁Pier ce y ▁which ▁has ▁a ▁ten - nit ro gen ▁chain . ▁The ▁record ▁was ▁later ▁taken ▁by ▁a ▁N 1 1 ▁chain ▁comp ound ▁synth es ized ▁by ▁a ▁group ▁of ▁Chinese ▁research ers . ▁A ▁branch ed ▁chain ▁N 1 1 ▁system ▁has ▁also ▁been ▁reported ▁as ▁part ▁of ▁an ▁un stable ▁but ▁highly ▁nit ro gen ▁rich ▁az id ot et raz ole ▁derivative