Sulfonate salts have the formula: R.sup.1SO.sub.3--CH(Rf)--CF.sub.2SO.sub.3.sup.-M.sup.+ wherein R.sup.1 is alkyl or aryl, Rf is H or trifluoromethyl, and M.sup.+ is a Li, Na, K, ammonium or tetramethylammonium ion. Onium salts, oximesulfonates and sulfonyloxyimides and other compounds derived from these sulfonate salts are effective photoacid generators in chemically amplified resist compositions.