Electronegativity, of cations

Solid metal sulphates and phosphates also exhibit acid—base properties their acid strength is lower than that of silica—alumina but they are stronger acids than some oxide catalysts [5]. Correlation of activity with electronegativity of cations has been obtained for several reactions [9, 50,51],... 

In a study of the water-gas shift activity of bulk oxides the electronegativity scale of Zhang (53) was shown to correlate catalytic activity (40). The results of the present study for the supported samples can also be interpreted in this manner. The electronegativity of cations included in this study increase in the order = Zn < Fe = < Tl = (see Table... 

TABLE 1. Tetrahedral Radii of Atomic Cores rT, Electron Affinities N, and Electronegativities of Cations and Anions... 

Fortier, J., Campet, G., Etoumeau, J., and Tanguy, B. A simple model for the estimation of electronegativities of cations in different electronic states and coordinations. J. Alloys Compd. 1994, 209, 285-289. 

In addition to the Zachariasen and radius ratio rules, for oxides the electronegativity of the predominant cation should be between 1.7 and 2.1 (7). If the cation electronegativity is too high, the compound tends to form molecules or discrete polyatomic ions rather than a connected network. For example, CrO satisfies the radius ratio rule, but the highly electronegative Cr ions promote the formation of discrete dichromate(VI) ions, Cr202 , in the presence of other oxides. 

The majority of the spin density is on nitrogen due to the high electronegativity of the sulfoxide sulfur. This is shown by the low g factor and high proton and nitrogen splitting compared to the bis(dimethylamino)sulfide cation. 

Let us extend our discussion of the [Fe(H20)6p cation a little further. The electronegativities of oxygen and hydrogen are 3.4 and 2.2 respectively, and the 0-H bond should thus be polarized in the sense The electroneutrality... 

The bonding electrons in CO and CO2 are polarized in the direction of the O atoms, as shown by the electronegativities of C (2.5) and O (3.5). Thus, if these substances were ionic, CO would consist of C cations and O anions, and CO2 would contain cations and O anions. Accordingly, we assign O an oxidation number of-2 in both these compounds, whereas C has an oxidation number of +2 in CO and +4 in CO2. ... 

Lux (1939) introduced the symbol pO (note it is not an exponent like pH) to quantify the acid-base balance in a glass, and various attempts have been made to obtain values for this parameter. All are based on the electronegativity of the cation or a related characteristic, such as electrostatic field strength (Volf, 1984). 

Although the work discussed thus far has covered primarily neutral organic radicals, there are many types of cation and anion radicals that are stabilized on the surface. Some of these ion radicals are formed through photochemical processes however, many others are spontaneously generated on a surface. The type of radical ion that is formed depends on the oxidizing or reducing character of particular sites on the surface, as well as on the ionization potential and the electronegativity of the adsorbed molecule. 

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