The Heteropolar Linkage Between Oppositely Charged Ions

We are indebted to W. KosseP and G. N. Lewis for the simple and successful theories of closed inert gas-like electron shells which are produced from the atoms of the chemical elements by the loss of loosely bound electrons (valence electrons) or by the acquisition of such electrons, thereby forming extremely stable systems. The atoms lose their motile electrons or replenish their unsaturated shells and are thus converted into positive or negative ions. 

If the electron clouds of these ions are not too large—as in the elements at the beginning of the Periodic System—they may be considered as nearly rigid, charged spheres, which are attracted by virtue of their electric charges. The equilibrium position is produced by the co-action of a force of attrac- 

On passing to heavier elements, the charge clouds become larger and less rigid, so that those, particularly of the negative anions, are deformed under the influence of the forces of attraction of the cations. This polarization or deformation of the ions which has been especially studied by 

Langmuir, Haber and Fajans gives rise to an additional force of attraction whose potential may be calculated by 

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