5,6-bis(methylene)bicyclo[2.2.1]hept-2-ene InChI=1/C9H10/c1-6-7(2)9-4-3-8(6)5-9/h3-4,8-9H,1-2,5H bicyclo[2.2.1]hept-2-ene, 5,6-bis(methylene)-