1H-cyclobuta[b][1]benzopyran, 2,2a-dihydro-2-phenyl- 2-phenyl-2,2a-dihydro-1H-cyclobuta[b]chromene InChI=1/C17H14O/c1-2-6-12(7-3-1)15-11-14-10-13-8-4-5-9-16(13)18-17(14)15/h1-10,15,17H,11H