Electronegativity ionic character

The greater the difference in electronegativity, the greater is the ionic character of the bond. The amount of ionic character I is given by ... 

FIGURE 2.13 The dependence of the percentage ionic character of the bond on the difference in electronegativity, A, between two bonded atoms for a number of halides. 

A number of years ago an equation was proposed13 for calculating the partial ionic character of a a bond between two atoms A and B from their electronegativity difference sa — b... 

Partial Ionic Character op Bonds in Relation to Electronegativity Difference... 

The discussion of interatomic distances in salts of oxygen acids of the second-row elements is presented in Table IV. In the first row of this table, below the names of the salts, there are given values of the electronegativity difference xa — xb, in the second row the sum of the single-bond radii, in the third row the Schomaker-Stevenson correction, and in the fourth row the single-bond interatomic distance. The next row contains the fractional amount of ionic character of the a bond, as given by the electronegativity difference with use of Table... 

The transfer of an electron to the iron atom is compatible with the electroneutrality principle. The electronegativity of iron is 1.8, leading to 12% ionic character of the iron-carbon bonds and to the satisfactory value +0.04 for the resultant charge on an iron atom that has accepted an electron and is forming nine bonds with carbon atoms. 

Ionic Bonding, Partial Ionic Character, and Electronegativity... 

Fig. 5.—In this figure ordinates and abscissas represent loci on the electronegativity map, and the heavy vertical lines are drawn to the height A, the observed deviation from additivity of bonds, attributed to their ionic character. Equation 1 in the text requires that these heights increase with the square of the distance from the diagonal.

The quantum mechanical argument used in deriving the original electronegativity scale involved the amount of ionic character of a normal covalent bond A—B, and it was evident that the amount of ionic character and accordingly the value of the electric dipole moment of the bond would be closely correlated with the difference Ax = xA — xB of the two atoms A and B. In the first edition of The Nature of the Chemical Bond (1939) the following equation was advanced ... 

In the above discussion the effect of difference in electronegativity of unlike atoms on bond length (usually a decrease) has been ignored. There is the possibility also of a small change in bond length between unlike atoms, such as of a metal and a metalloid, that reflects the difference in the nature of the overlapping orbitals, in addition to the effects of partial ionic character and of electron transfer. I believe that a thorough... 

Chapter 2. Ionic Bonding, Partial Ionic Character, and Electronegativity Papers SP 23 to SP 27 255... 

When the difference in electronegativities is great, the orbital may be so far over to one side that it barely covers the other nucleus. This is an ionic bond, which is seen to arise naturally out of the previous discussion, leaving us with basically only one type of bond in organic molecules. Most bonds can be considered intermediate between ionic and covalent. We speak of percent ionic character of a bond, which indicates the extent of electron-cloud distortion. There is a continuous gradation from ionic to covalent bonds. 

Substituting A1 atoms for Ga atoms does not change the lattice dimensions, which are determined by the size of As, the largest atom of this set. Here, the lower electronegativity of A1 relative to Ga leads to more ionic character and a smaller band gap. 

Relationship Between Electronegativity Difference and Ionic Character ... 

Electronegativity difference Type of bond Percent ionic character... 

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