Carbon atoms ionic bond formation

Processes accompanied by a decrease in volume, such as C—C bond formation, in which the distance between two carbon atoms decreases from the van der Waals distance of ca 3.6 A to the bonding distance of ca 1.5 A, are accelerated by raising the pressure and equilibria are shifted toward the side of products (AV < 0, AV < 0). The reverse reaction, a homolytic bond cleavage, leads to an increase in volume (AV / > 0, AV > 0). Pressure induces a deceleration of such a process and a shift in equilibrium toward the side of reactants. However, in an ionization, such as an ionic dissociation, the attractive interaction between the ions generated and the solvent molecules leads to a contraction... 

The same principles that are valid for the surface of crystalline substances hold for the surface of amorphous solids. Crystals can be of the purely ionic type, e.g., NaF, or of the purely covalent type, e.g., diamond. Most substances, however, are somewhere in between these extremes [even in lithium fluoride, a slight tendency towards bond formation between cations and anions has been shown by precise determinations of the electron density distribution (/)]. Mostly, amorphous solids are found with predominantly covalent bonds. As with liquids, there is usually some close-range ordering of the atoms similar to the ordering in the corresponding crystalline structures. Obviously, this is caused by the tendency of the atoms to retain their normal electron configuration, such as the sp hybridization of silicon in silica. Here, too, transitions from crystalline to amorphous do occur. The microcrystalline forms of carbon which are structurally descended from graphite are an example. 

In the equilibrium structure, the main VB structure is the covalent CH bonds structure (I) as expected. The second most important are those where one of the CH bonds is connected with a covalent bond and the other with an ionic bond made by electron transfer from the hydrogen atom to the carbon atom, (II) and (IV). In contrast, the contribution from the structures that describe electron transfer from the carbon atom to a hydrogen atom is small and negative. The contribution from the HH bond structure (VIII) and ionic structures, (IX) and (X), is very small. The total occupation number of CH bonds is 0.9654, while that of HH bond is -0.0147. This indicates almost no bond formation between two hydrogen atoms in the equilibrium structure. 

Elimination of carbon dioxide and abstraction of a fluoride ion result in the formation of a terminal C = C bond. The new alkene has one carbon atom fewer than the original carboxylic acid. The mechanism of the reaction is ionic. 

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