Patent ID: 8124803

Claim:
A salt of one of the following formula (I) or formula (II): wherein ring x represents monocyclic or polycyclic hydrocarbon group having 3 to 30 carbon atoms, and at least one hydrogen atom in the monocyclic or polycyclic hydrocarbon group may optionally be substituted with alkyl group having 1 to 6 carbon atom, alkoxy group having 1 to 6 carbon atom, perfluoroalkyl group having 1 to 4 carbon atoms, hydroxyalkyl group having 1 to 6 carbon atoms, hydroxyl group or cyano group; R 10 and R 20 each independently represent fluorine atom or perfluoroalkyl group having 1 to 6 carbon atoms; and A + is at least one cation selected from the group consisting of the formula (IIIa), the formula (IIIb), the formula (IIIc) and the formula (IIId): a cation of the formula (IIIa) wherein P 1 , P 2 and P 3 each, independently represent hydrogen atom, hydroxyl group, alkyl group having 1 to 12 carbon atoms or alkoxy group having 1 to 12 carbon atoms; a cation of the formula (IIIb) wherein P 4 and P 5 each independently represent hydrogen atom, hydroxyl group, alkyl group having 1 to 12 carbon atoms or alkoxy group having 1 to 12 carbon atoms; a cation of the formula (IIIc) wherein P 6 and P 7 each independently represent alkyl having 1 to 12 carbon atoms or cycloalkyl having 3 to 12 carbon atoms, or P 6 and P 7 bond to form divalent acyclic hydrocarbon group having 3 to 12 carbon atoms which forms a ring together with the adjacent S + , and at least one —CH 2 — in the divalent acyclic hydrocarbon group is optionally substituted by —CO—, —O— or —S—, P 8 represents hydrogen, P 9 represents alkyl having 1 to 12 carbon atoms, cycloalkyl having 3 to 12 carbon atoms or aromatic ring group optionally substituted, or P 8 and P 9 bond to form divalent acyclic hydrocarbon group which forms 2-oxocycloalkyl together with the adjacent —CHCO—, and at least one —CH 2 — in the divalent acyclic hydrocarbon group is optionally substituted by —CO—, —O— or —S—; and a cation of the formula (IIId) wherein P 10 , P 11 , P 12 , P 13 , P 14 , P 15 , P 16 , P 17 , P 18 , P 19 , P 20 and P 21 each independently represent hydrogen atom, hydroxyl group, alkyl group having 1 to 12 carbon atoms or alkoxy group having 1 to 12 carbon atoms, B represents sulfur atom or oxygen atom, and m represents 0 or 1.