3,4-dihydrocyclobuta[c]phenanthrene-1,2-dione InChI=1/C16H10O2/c17-15-12-8-7-10-6-5-9-3-1-2-4-11(9)13(10)14(12)16(15)18/h1-6H,7-8H cyclobuta[c]phenanthrene-1,2-dione, 3,4-dihydro-