Layer charge density

FIG. 3 Orientations of alkylammonium ions in the galleries of clay layers with different layer charge densities. (From Ref. 28.)... 

LDH Host Features Local Structure and Layer Charge Density. 135... 

In the case of LDH hosts, since only the average structure is known, it is important to consider the local structure by means of X-ray absorption spectroscopy extended X-ray absorption fine structure (EXAFS). According to an ideal model based on edge-sharing octahedra [64], it is possible to define the local environment around each type of cation in relation to the layer-charge density. Figure 11 shows the local cation environment for LDH with... 

Eq. (3.92) implies a linear relation between cosh Y0 and cosh Ym. Therefore, values for go., and Fo, can be assessed by extrapolating this relation to cosh Ym = 1. This is demonstrated in Fig. 3.46 where a plot of cosh Yg versus cosh Ym is shown. Making use of least-squares analysis we obtain a slope of 1.01 0.01 and an intercept of 1.80 0.4. Furthermore, in conformity with Eq. (3.92) the intercept yields Fo, = 119 0.03 or, respectively, (po = 30.5 0.7 mV and <70i = 1.29 0.04 mC m 2 for the diffuse electric layer potential and diffuse double layer charge density at infinite separation. These values are in... 

The oxidized layer charge densities and interface state densities are reported in table 11. 

As the stability of the graphitic phases probably relates to the intralayer structure than the interlayer spacing we investigate the layer charge density for the phases. In Fig. 5 we show the charge density of the P6 /m phase rather surprisingly most of the charge on N is directed away from the C-N bond toward the vacant site, as is the case for some superhard structures. 

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