Definition of nanostructure
Owing to the very large number of nanostructure types with strongly differing shapes (let's compare, for example, graphene with fullerenes or SW-CNTs with atomic clusters)^[1], it is quite difficult to formulate an universal definition for such a type of advanced material. However, based on some features common to all kinds of nanostructures, the following definition could be developed:
"Nanostructures are artificial or natural tiny solid corpuscles, belonging to the microscopic world and precisely to the nanoscopic dimensional scale (that is, 10^-9m), that are characterized by anomalous chemical and physical properties in comparison with the corresponding bulk (massive) solid phases, because of effects like: quantum-confinement, band structure discretization, prevalence of surface on bulk matter, change of the prevaling type of surface atoms, high surface free energy content, etc. and these properties can be widely tuned by morphological variations (i.e., by nanostructure size and shape modification)."