1,3-cyclopentanedione, 2-(2,4,6-cycloheptatrien-1-ylidene)- 2-cyclohepta-2,4,6-trien-1-ylidenecyclopentane-1,3-dione InChI=1/C12H10O2/c13-10-7-8-11(14)12(10)9-5-3-1-2-4-6-9/h1-6H,7-8H