Pauling ionicity

Table 1.4. Phillips Pauling ionicity parameters for some A B crystals...

Data compiled from F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry , 4th edn., Wiley, New York, 1980. Pauling ionic radii are quoted. 

The quantities E and A are constants for each class of ions, and E-q and Ag have been determined by a linear plot of 1/A( g with the Pauling ionic radius in Figure 3 which gave ffg and fig values of 656,5 kJ.nm-mol l and 0.0753 nm respectively for the cations and 492.9 kJ nm mol and -0.0180 nm respectively for the halide ions. These are compared to those for water in Table IV. 

Solving Equations (12.9) and (I2.I0) simultaneously for r+ and r, where the interionic distance in the crystal is known, yields the univalent radii. Univalent radii assume that the ions interact using a hard-spheres model such that their electron clouds do not interpenetrate with one another. For ions that are not univalent, such as Mg " ", a correction must be made for the compressibility because the larger the nuclear charge, the more likely the ion will be able to polarize the electron cloud of its neighbor. The correction factor, shown in Equation (12.14) can be derived from the Born constant, as demonstrated below in Equations (12.11)-(12.13). The corrected Pauling ionic radii for selected ions are listed in Table 12.5. 

Example 12-7. Employ the radius ratio rule using the Pauling ionic radii listed in Table 12.5 to predict the lattice types of (a) CsCI, (b) SrF2, and (c) KBr. 

Pauling ionic radii of the isotopes in question. The difference of the Pauling radii for Li and Li is 0.04 pm, Li being smaller. 

The bulk AI2O3 contains A1 octahedra that share oxygen atoms. The Pauling ionic bond strength of an Al-0 bond with respect to A1 is... 

The Brpnsted acidity or basicity of the hydroxyl groups in Scheme 5.1 can be dednced from the Pauling ionic charge excesses ... 

Table 5. Comparison of relative bare Pauling ionic diameters The smallest cation as well as the smallest anion correspond to the 100% value.

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