Differences between the Elements Silicon and Carbon

Characteristic Differences between the Elements Silicon and Carbon 

Elementary silicon is also of principal importance to the covalent chemistry of silicon, because all pathways to such silicon compounds involve the element itself. Of course, the silicate systems are distinctly separate. Their properties and uses arise from the high strength of the silicon—oxygen bond. To illustrate the differences between related compounds of carbon and silicon, some bond energies and bond distances are shown in Table 1. More recent compilations give considerably higher Si—X bond energies [66]. 

The differing electronic configurations of silicon and carbon must also be taken into consideration. Silicon d orbitals are arranged in such a way as to make possible the formation of a pentacovalent or hexacovalent state. The hydrolytic cleavage of the Si—Cl bond, for example, may proceed through a pentacovalent transition state. The existence of silicon compounds with coordination numbers 5 and 6 can be substantiated through the same reasoning [3]. 

The variety of reactions possible for any element arises mainly from the number and properties of its functional groups. To name just one important branch of the many possibilities in the chemistry of carbon, the 

The number of functional groups associated with the element silicon is considerably smaller, and confined primarily to the Si-halogen, Si—H, Si—OH, Si—OR, Si—N and Si—P groups. The Si—OH group tends to eliminate H O and form Si—O—Si bonds provided no steric reasons prevent this condensation. Silicon is not capable of forming stable Si = 0 double bonds. 

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