Patent ID: 7312252

Claim:
A composition of matter comprising anionic clay having the general formula [M 2+ 1-x M 3+ x (OH) 2 ] x+ (x/n)A n− ·yH 2 O (I) where M 2+ is a divalent metal; and M 3+ is a trivalent metal; A is an inorganic or organic anion, chosen such that the rule of charge neutrality is obeyed; n is an integer; x is a rational number between 0.01 an 0.5; and y is any rational number between 0 and 10; where the anionic clay is in the form of particles having a volume weighted mean particle size diameter of less than 500 nm and where at least 90 volume percent of the particles of the anionic clay composition have a diameter smaller than 200 nm.