Patent ID: 7759420

Claim:
A layered silicate characterized by being ion-exchanged with an organic onium ion represented by the following formula (1): wherein R 1 , R 2 , R 3 and R 4 each independently represent a C1-30 hydrocarbon group or a heteroatom-containing hydrocarbon group, M is a phosphorus atom to form a phosphonium group, or M is a nitrogen atom and any of R 1 , R 2 , R 3 and R 4 form a ring as a heteroaromatic ion, and at least a portion of R 1 , R 2 , R 3 and R 4 is an imide-substituted hydrocarbon group, at 50-100% of its ion-exchange capacity, and by having a specific surface area of 2.5-100 m 2 /g.