2,2,4,5-tetrachlorocyclopent-4-ene-1,3-dione

2,3,4,4,5,5-hexachlorocyclopent-2-en-1-one

2,3,4,5,6,7-hexachloroinden-1-one

2,3,4,4,5-五氯环戊-2-烯-1-酮

甲烷离子(2+)