Carbon nanostructures

Carbon is a tetravalent element, which is the 15th most abundant element in the Earth crust and the fourth most abundant one in the universe. Carbon is capable of forming many allotropes (i.e., structurally different forms of the same element), including graphite, diamond, amorphous carbon, fullerenes, carbon nanotubes, glassy carbon, and others. The variety of allotropes in this monoatomic material originates from different possible hybridizations of the covalent carbon–carbon bonds (sp, sp2, sp3). In addition, when combined with other elements, it forms a plethora of organic compounds and polymers with various physical and chemical properties. This chapter focuses specifically on the nanoparticles comprising different allotropes of monoatomic carbon, while nanoparticles consisting of organic and polymer compounds are discussed in the fifth and sixth chapters, respectively.