Dependence of Force Constant on Electronegativity, Bond Strength, and Bond Order. VII

Abstract

The expression :kAB=(kAA·kBB)12+Δ where k′S are the force constants of the bonds AA, AB, and BB of given type and Δ, an ionic contribution term, has been suggested. For single bonds, the value for √Δ corresponds to the difference in the electronegativities of the atoms A and B in their valence states. In the case of multiple bonds the value for √Δ leads to proper value for the percentage ionic character of the bond. Force constant has been shown to be proportional to the product of the strengths of the bond orbitals, the magnitude of a bond orbital in its angular dependence being defined as the strength with value 1 for an s orbital and 1.732 for a p orbital. The value for the sp3 orbital has been found to be about 2 but for sp2 and sp orbitals, values differing from those suggested by Pauling have been obtained. Among s—p bonds, digonal bonds have been shown to be the strongest followed by trigonal and tetrahedral bonds. In alkali metals, the bonds have been shown to be s—p bonds with strength 1.732. Force constant has been shown to be linearly related to bond order. Finally, values for the force constants of various covalent bonds have been assigned.