1,2,7,8-Dibenzopyrene 189-55-9 3,4,9,10-Dibenzopyrene 3,4:9,10-Dibenzopyrene 3,4:9,10-Dibenzpyrene Benzo[r,s,t]pentaphene Benzo[rst]pentaphene Db(a,i)p Dibenz[a,i]pyrene Dibenzo-3,4,9,10-pyrene Dibenzo[a,i]pyrene NSC87521 WLN: L D6 B66 P666 2AB A & J