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In one aspect, the invention provides a sulfonium salt hav› ing the general formula (1 ). 

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Herein R 0 is hydrogen, or a straight C$_{1}$-C$_{20 }$ or branched or cyclic C$_{3}$-C$_{20 }$monovalent hydrocarbon group which may be substituted with or separated by a heteroatom; R$^{O 1 }$and R $^{02 }$are each independently hydrogen, or a straight C$_{1 }$-C$_{20 }$ or branched or cyclic C$_{3 }$-C$_{20 }$ monovalent hydrocarbon group which may be substituted with or separated by a heteroatom, or R 01 and R$^{02 }$may bond together to form a ring with the carbon atom to which they are attached, with the proviso that at least one ofR 0 , R $^{01 }$and R$^{02 }$has a cyclic structure; Lis a single bond or forms an ester bond, sulfonate bond, carbonate bond or carbamate bond with the vicinal oxygen atom; R 2 , R 3 and R$^{4 }$are each independently a straight C$_{1 }$-C$_{20 }$or branched or cyclic C$_{3}$-C$_{20 }$monovalent hydrocarbon group which may be substituted with or separated by a heteroatom, at least two ofR 2 , R 3 and R 4 may bond together to form a ring with the sulfur atom in the formula. 

In a preferred embodiment, the anion moiety of the for- mula: 

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is selected from the following formulae (A-9) to (A-16), (A-27) to (A-34), (A-44) to (A-50), (A-52), and (A-53). 

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-continued 

