Homopolar binding

Heitler, W. and London, F. 1927. Interaction of neutral atoms and homopolar binding according to the quantum mechanics. Z. Phys. 44 455 -72. 

In the first place, we can symbolize the process of forming a homopolar bond by a simple device used by G. N. Lewis, to whom many of the ideas of homopolar binding are due. Most of the elements forming this type of bond are trying to complete a shell, or subshell, of eight electrons, as we... 

The binding of valence crystals can also be explained from the standpoint of energy bands. In Fig. XXIX-12 we show energy bands for diamond, a typical crystal held by homopolar bonds. We see that the... 

The chemist at present must be satisfied with the knowledge that the repulsive forces depend on rather subtle details of the charge distribution of the molecules, and that consequently there is no reason to hope that one might connect them with other simple constants of the molecules, as is possible for the far-reaching attractive forces. Their theoretical determination is in any special case another problem of pure numerical calculations. But what really will interest the chemist is the fact that it can generally be shown that these homopolar repulsive forces (in characteristic contrast with the above-mentioned homopolar binding forces) have also the property of additivity, in the same approximate sense as the forces are additive, and that, therefore, to a first approximation, it will be quite justified to assume for the repulsive forces also simple analytical expressions, to superpose them simply additively and so to try to determine them from empirical data of the liquid or solid state. Whereas formerly one used to presume a power-law of the form bjR for these repulsive forces, quantum mechanics now shows that an exponential law of the form... 

Atomic bindings with saturation of valency valency bindings (also called homopolar bindings)] to these belong in the first place the diatomic gases, such as Hg, Ng, O2, as well as most organic compounds, for instance, CH4. 

The nomenclature is not quite lixed, but that given here seems to be gradually becoming established. As a matter of history, it ma,y bo noted that the distinction between heteropolar and homopolar binding was first drawn by Abcgg the separation into ionic and atomic binding, with the criterion of the dissociation products, was introduced by Franck. 

On account of the great binding energy of the homopolar valence, all these substances are very compact, high melting, hard crystals, some of which have considerable technical importance. 

For homopolar chemical binding, the fermionic diatomic potential, in atomic units, is considered with the working form (Putz, 2012d)... 

The molecular chemical hardness may be set equal to that of atomic species entering homopolar binding, according to molecule softness (5) based formulation rooted in the Bratsch atoms-in-molecule approach (Bratsch, 1985)... 

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