Layered double hydroxides: Structure, synthesis, properties and applications.

The layered double hydroxides, known as anionic clays and represented by the general formula [M-1-x(2+), M-x(3+), (OH)(2)](X+) A(x/m)(m)-. nH(2)O, are a group of materials which are of much interest currently. They present a variety of potential applications as adsorbents, catalysts and catalyst support, ion-exchangers, antacids and as a polymer stabilizer. It is possible to obtain a broad variety of layered double hydroxides (LDHs), depending on the identity and ratio of the cations M2+ and M3+, as well as the interlamelar anion. The aim of this review is to give out some information about this class of materials, concerning to the synthesis, characterization, properties and applications.