2-NORBORNENE 2-Norbornylene 27416-03-1 3,6-Endomethylenecyclohexene 498-66-8 8,9,10-Trinorborn-2-ene Bicyclo(2.2.1)hept-2-ene Bicyclo(2.2.1)heptene EINECS 207-866-0 NSC 120425 Norbornene Norbornylene Norcamphene Norfenchene