Zeolite mean Sanderson electronegativities

Fig. 32. H NMR shifts, 6n, of bridging OH groups in the supercages and channels of aluminosilicate type zeolites as a function of the mean Sanderson electronegativity Sm [222] given in columns 5 and 6 of Table 5 and in [220]...

A detailed infrared study of pyrrole adsorption on a series of zeolites saturated with alkaline cations shows that the Avnh increase depends on two parameters, a high A1 content and a low electronegativity of the cation i.e. Cs rather than Li (62,66,67). The experimental Avnh values in figure 10 show a good relationship with the mean charge on the framework oxygen calculated from Sanderson electronegativity (62,67). 

Recently Jacobs (84, 85) has proposed another system of structural hydroxyls in zeolites based on the mean electronegativities of zeolite lattices according to Sanderson. It was concluded as well that the Bronsted acidity of zeolites varies continuously with their Si/Al content. Let us compare these two approaches. 

Zeolites are composed of various atoms of different electronegativity (refer to Table 2.8). However, their intermediate electronegativity (i.e., geometric mean of the component atoms after redistribution of the electrons in the compound) is reported to be established as demonstrated hy Sanderson s principle of electronegativity equalization (i.e., when two or more atoms initially different in electronegativity combine chemically, they become adjusted to flie same electronegativity within the compound). The intermediate electronegativity can be determined for a compound, Qv, by Eq. (2.1) [59] ... 

---