Sepiolite structural formulas

Attapulgite and sepiolite data plot on both sides of the neutral line.. The calculated structural formulas of these two clays are more subject to error than those of the sheet structure clays. As is suggested by their low cation exchange capacity octahedral sheets tend to approach neutrality. The amount of R3+ required to maintain neutrality is less if OH substitues for O2. ... 

Fig. 2 Structural models and ideal formulae of sepiolite and palygorskite fibrous clays [26]...

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