3,6-bis(4-nitrophenyl)-6,7-dihydro-5h-[1,2,4]triazolo[3,4-b][1,3,5]thiadiazine (en)5h-1,2,4-triazolo[3,4-b][1,3,5]thiadiazine, 6,7-dihydro-3,6-bis(4-nitrophenyl)- (en)