4,9-Dihydro-1,3,6,8-tetranitro-pyrido(2,3,4,5-lmn)phenanthridine-5,10-dione 56181-16-9 Pyrido(2,3,4,5-lmn)phenanthridine-5,10(4H,9H)-dione, 1,3,6,8-tetranitro-