(1Z)-2,2',3,3'-tetrahydro-1,1'-biindene (Z)-2,3,2',3'-Tetrahydro-[1,1']biindenylidene 1-(1-Indanyliden)indan 17666-94-3 2,3,2',3'-Tetrahydro-[1,1']biindenylidene InChI=1/C18H16/c1-3-7-15-13(5-1)9-11-17(15)18-12-10-14-6-2-4-8-16(14)18/h1-8H,9-12H2/b18-17