1 2 3 7 8 9 hexahydropyren July 8, 2019 16 32 64 128 Tetrabromo-1 2 3 7 8 9-hexahydropyren 1 2 3 5 6 7-hexahydronaphthalene 1 3 4 6 7 8-hexahydro-4 6 6 7 8 8-hexamethylindeno 5 6-c pyran 1 3 5-hexatriene