Carbons on the Nanoscale

We have seen that elemental carbon is quite versatile. In its bulk sp -hybridized solid-state form, it is diamond in its bulk sp -hybridized solid-state form, it is graphite. Over the past three decades, scientists have discovered that sp -hybridized carbon can also form discrete molecules, one-dimensional nanoscale tubes, and two-dimensional nanoscale sheets. Each of these forms of carbon shows very interesting properties. 

The fact that carbon nanotubes can be made either semiconducting or metallic without any doping is unique among solid-state materials, and laboratories worldwide are making and testing carbon-based electronic devices. Carbon nanotubes are also being explored for their mechanical properties. The carbon-carbon bonded framework of the nanotubes means that the imperfections that might appear in a metal nanowire of similar dimensions are nearly absent. Experiments on individual carbon nanotubes 

Polymers that can conduct electricity are called conducting polymers. Some polymers can be made semiconducting others can be nearly metallic. Polyacetylene is an example of a polymer that is a semiconductor. It can also be doped to increase its conductivity. 

Polyacetylene is made from acetylene in a reaction that looks simple but is actually tricky to do  

Ana lyze For part (a), we need to recall what we have learned about sp, sp, and sp hybridization and geometry. aao(Section 9.5) For part (b), we need to write a balanced equation. For part (c), we need to use the ideal-gas equation, oao (Section 10.4) For part (d), we need to recall the definitions of endothermic and exothermic and how bond enthalpies can be used to predict overall reaction enthalpies. aao(Section 8.8) For part (e), we need to relate the absorption of light to the differences in energy levels between filled and empty states in a material. oao(Section 6.3) 

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