Electronic displacement in covalent bonds
It is examined that most of the attacking reagents all time possess either a positive or a negetive charge, hence for a solution to operate on the covalent bond the latter must possess oppositely charged centres. This is made feasible by displacement (partial or complete) of the bonding electrons. The electronic distance in turn can be because of specific effects, some of which are fixed and others are temporary. The previous effects are permanently performing in the atom and are known as polarisation effects, when the latter are taken into play by the attacking reagent and once the attacking reagent is replaced, the electronic distance disappears; such types of effects are termed as the polarisability effects.