Generalisations of the Lewis Structures

3 Extensions of the Lewis/Kossel Model 3.1 Generalisations of the Lewis Structures 

The discussion above has indicated some of the limitations of the original Lewis/ Kossel descriptiOTi of chemical bonding and the manner in which it has been adapted to assimilate the multitude of new compounds being reported from chemical laboratories during the last century. Central to the model is the definition of the chemical bond as a pair of electrons and the adherence to the octet rule. 

The relevance of completed electronic shells associated with the inert gases was extended by Langmuir [42—45], who developed specific formulae relating the covalence of the central atom to the number of valence electrons in the inert gases. Since the atomic numbers of the inert gases are 2, 10, 18, 36, 54 and 

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