Hectorite Modeling

As an example, infrared spectroscopy has shown that the lowest stable hydration state for a Li-hectorite has a structure in which the lithium cation is partially keyed into the ditrigonal hole of the hectorite and has 3 water molecules coordinating the exposed part of the cation in a triangular arrangement (17), as proposed in the model of Mamy (J2.) The water molecules exhibit two kinds of motion a slow rotation of the whole hydration sphere about an axis through the triangle of the water molecules, and a faster rotation of each water molecule about its own C axis ( l8). A similar structure for adsorbed water at low water contents has been observed for Cu-hectorite, Ca-bentonite, and Ca-vermiculite (17). 

CJ. Hartzell et al., Molecular modeling of the tributyl phosphate complex of europium nitrate in the clay hectorite. J. Phys. Chem. A 102, 6722-6729 (1998)... 

Hartzell CJ, Cygan RT, Nagy KJ (1998) Molecular Modeling of the Tributyl Phosphate Complex of Europium Nitrate in the ( lay Hectorite, J Phys Chem A 102(34) 6722-6729... 

Figure 15.11. Tensile modulus of composites made from nylon and different fillers (montmorillonite, saponite, hectorite and mica) vs. N-NMR chemical shifts of model compounds of fillers. [Adapted, by permission, from Usuki A, Koiwai A, Kojima Y, Kawasumi M, Okada A, Kurauchi T, Kamigaito O, J. Appl. Polym. Sci., SS, No.l, 1995, 119-23.]...

A polyhedral model of hectorite is shown in Figure 3 of [97]. Figure 1 of [98] shows ball-and-stick model of kaolinite. A combined polyhedral/ball-and-stick model of kaolinite is shown in Figure 1 of [99]. A ball-and-stick model of kaolinite is shown in Figure 1 of [100]. A ball-and-stick model of the 010 plane of montmorillonite is shown in Figure 1 of [101]. Ball-and-stick models of kaolinite, pyrophyllite, and illite are shown in Figure 7 of [60]. 

FIGURE 9 Model deduced from the NMR specttum of benzene/Ag-hectorite com-... 

FIGURE 9 Model deduced from the NMR spectrum of benzene/Ag-hectorite complex for the average orientation of CeHe molecules between the clay layer. (After Ref. 251. With kind permission of Kluwer Academic Publishers.)... 

Figure 3. Talc, reference model of trioctahedral smectites. A— hexagonal cavities H and S— eventual localization of the negative charges created by isomorphous replacements H—octahedral charges (hectorite) S— tetrahedral charges (saponite).

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