Structure of the Carbon Atom

The landmark in the history of conformation started in 1874 when van t Hoff and Le Bel gave the tetrahedral structure of the carbon atom in which the angle between the valency bonds was... 

The electronic structure of the carbon atom is designated as Is2,2s2,2p, 2Py (Figure 2.4) and this means that in order to fill all the available orbitals... 

We now give a discussion of each of the molecules, first considering the atomic structure of the carbon atom and attempting to predict the bonding pattern. The predictions are followed by the results of the ST03G calculations. 

Quite apart from their singular topology, the fullerenes are distinguished from other conjugated hydrocarbons by their non-planarity. The geometrical aspects of fullerene formation as it relates to pyramidalization of the constituent carbon atoms has been recognized for some time (Haddon et al. 1986 Haddon 1988). Here we consider the effect of non-planarity on the electronic structure of the carbon atoms as it arises in the fullerenes (Haddon et al. 1986 Haddon 1992). 

The electronic structure of the carbon atom gives the element a remarkable diversity of chemical properties. The four valence electrons occupy the configuration 2s 2p in the ground state but promotion and hybridisation (p. 97) occurs very freely and accounts for the characteristic valency of four which is never exceeded. Silicon differs in that 3d orbitals are accessible, giving a greater variety and an increased number of valencies (p. 104). It can thus exhibit a covalency greater than 4, as in the SiFg ion. 

To explain a good deal of the chemistry of carbon, we need to call upon the concept of hybridisation. The electronic structure of the carbon atom is s12s12p1x2p] . All the orbitals of principal quantum number 2 are of similar energy, and we can visualise a hybridisation involving the 2s,... 

The electronic structure of the carbon atom in its ground state is s22s22p2, with the two 2p electrons unpaired, following Hund s rule. In order to account for the normal four-covalence of carbon, we must consider that it is promoted to a valence state based on the configuration 2s2px2py2pz. The ion C4+ does not arise in any normal chemical process the C4 ion may possibly exist in some carbides. In general, however, carbon forms covalent bonds. 

Fullernes form a group of carbon allotropes. There are spherical fullerenes nicknamed buckyballs and cylindrical fullerenes known as buckytubes or nanotubes. Fullerenes have yet to display all of their capabilities to scientists. One of the most promising areas of fullerene research involves the creation of nanotubes. Nanotubes are sheets of carbon that are rolled up into cylinders. These cylinders are strong—due to the hexagonal structure of the carbon atoms—and have unique conducting properties. Fullerene nano-technology on the horizon includes the development of faster computer chips, smaller electronic components, and more advanced space-exploration vehicles. 

Figure 3.1 Schematic representation of the electronic structure of the carbon atom.

In order to have a electron configuration that would account for this symmetry, the structure of the carbon atom must be altered to a state with four valence electrons instead of two, each in a separate orbital and each... 

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