Hectorite idealized formula

Mostly focused on cationic clays, and particularly on montmorillonite and hectorite, smectite-type layered silicates and clay-based nanofillers have recently been extended to the family of LDH. Hydrotalcite-like LDH materials are described according to the ideal formula, [M1/ xM"l(OH)2]frl(lra [A H20]inter, where Mn and Mm are metallic cations, A the anions, and intra and inter denote the intralayer and interlayer domain, respectively. The structure consists of brucite-like layers constituted of edge-sharing octahedra. The presence of trivalent cations induces positive charges in the layers that are counterbalanced by interlamellar anions (Scheme 15.16). 

Figure 1. The hectorite structure, an idealized, unit cell formula being Na0.tr [Lit., Mg,.st](Sig. )0,c(0H,F)t. Key O, oxygen , OH and occasionally fluoride. The tetrahedral sites are occupied mainly by silicon magnesium and lithium occupy the octahedral sites.

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