Patent ID: 8703969

Claim:
An S-(trifluoromethyl)-benzo[b]thiophenium salt represented by formula (1), wherein R 1 , R 2 , R 3 , and R 4 each independently represent a hydrogen atom, a methyl group, an ethyl group, a linear, branched, or cyclic alkyl group having 3 to 10 carbon atoms, a methoxy group, an ethoxy group, a linear, branched, or cyclic alkyloxy group having 3 to 10 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, a nitro group, or a cyano group, R 5 is a methyl group, an ethyl group, a linear, branched, or cyclic alkyl group having 3 to 10 carbon atoms, a phenyl group, or a substituted phenyl group, and X − represents an anion.