Cyclopentene 142-29-0 33004-05-6 29821_FLUKA NSC5160 WLN: L5UTJ EINECS 205-532-9 NSC 5160 UN2246 1-Cyclopentene InChI=1/C5H8/c1-2-4-5-3-1/h1-2H,3-5H Cyclopentene [UN2246] [Flammable liquid] 344508_ALDRICH