1,2,3,4-Tetrachloro-1,3-cyclopentadiene 1,2,3,4-Tetrachlorocyclopentadiene 1,3-Cyclopentadiene, 1,2,3,4-tetrachloro- 2,3,4,5-Tetrachlorocyclopentadiene 695-77-2 NSC18221 Tetrachlorocyclopentadiene