4-(chlorosulfonyl)benzenesulfonyl fluoride InChI=1/C6H4ClFO4S2/c7-13(9,10)5-1-3-6(4-2-5)14(8,11)12/h1-4 benzenesulfonyl fluoride, 4-(chlorosulfonyl)- p-fluorosulfonylbenzenesulfonyl chloride