Sanderson intermediate electronegativity

For a series of alkali metal ion-exchanged zeolites the N-H frequency of pyrrole is found to shift to lower wavenumbers as the Sanderson intermediate electronegativity (Sin of the zeolite increases. Since, the charge on the oxygen (Sq) is directly correlated with the intermediate electronegativity by,... 

One of the parameters in the broad class of liquid adsorption mechanisms is the interaction between the acidic and basic sites of the adsorbent and the adsorbate. The acidity of zeolitic adsorbent is normally affected by the zeolite Si02/Al203 molar ratio, the ionic radii and the valence of the cations exchanged into the zeolite. In this contribution, Sanderson s model of intermediate electronegativity of zeolitic adsorbent acidity (SjJ can be calculated as a representation of the strength of the adsorbent acidity based on the following equation ... 

Researchers attempted to find correlations between the composition of the unit cell and the selectivity for paraxylene. In this respect, D. Barthomeuf (9) proposed an approach based on Sanderson s intermediate electronegativity which allows us to estimate the basicity of zeolite oxygens, and hence the strength of the acid-base interaction between xylene molecules and zeolites. It should be noted that these calculations provide an insight into the interactions between the zeolite structure and the molecules at low loading only, i.e. when the interactions between adsorbed molecules are negligible. 

Distance between H of a SiOHAl group and C of an adsorbed CO molecule Distance between H of a SiOHAl group and O of an adsorbed CO molecule Sanderson s intermediate electronegativity Strength of gas phase acidity... 

Fig. 3 Values for Sanderson s intermediate electronegativity S as a function of the framework Si/Al ratio n and the proton exchange degree Csjohai/Cai HNa-zeolites...

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] ... 

In 1951, Robert Thomas Sanderson (1912-1989) introduced the principle of electronegativity equalization that proposes, when two or more atoms combine, the atoms adjust to the same intermediate Mulliken electronegativity (Sanderson, 1951). Density functional theory tells us that the Mulliken electronegativity is the negative of the chemical potential (Parr et al., 1978). Sanderson s principle then becomes very appealing in that it can be considered analogous to a macroscopic thermodynamic phenomenon - the equalization of chemical potential. When atoms interact, the electronegativity, or chemical potential, must equalize. 

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