三氯一氟甲烷 trichlorofluoromethane 75-69-4溴甲烷 bromomethane 74-83-9氯乙烯 vinylchloride 75-01-4一氯甲烷 chloromethane 74-87-3氯乙烷 chloroethane 75-00-3二氯二氟甲烷 dichlorodifluoromethane 75-71-8
