2,2'(1H,1'H)-spirobi[s-indacene], 3,3',5,5',6,6',7,7'-octahydro- 3,3',5,5',6,6',7,7'-octahydro-1H,1'H-2,2'-spirobi[s-indacene] InChI=1/C23H24/c1-3-15-7-19-11-23(12-20(19)8-16(15)4-1)13-21-9-17-5-2-6-18(17)10-22(21)14-23/h7-10H,1-6,11-14H