Natural atomic orbital uniqueness property

The orbital bonding nature within carbon nanotubes creates unique electrical properties within a non-metallic molecule, which is a result of the delocalization of the -electron donated by each atom. Electrical conductivity can take place along the entire nanotube due to the freedom of -electron flow, making possible the design of circuits of extremely low nanometer diameter. 

All elements, by definition, have a unique proton number, but some also have a unique number of neutrons (at least, in naturally occurring forms) and therefore a unique atomic weight - examples are gold (Au Z = 79, N = 118, giving A =197), bismuth (Bi Z = 83, N = 126, A = 209), and at the lighter end of the scale, fluorine (F Z = 9, N = 10, A = 19) and sodium (Na Z = 11, N= 12, A = 23). Such behavior is, however, rare in the periodic table, where the vast majority of natural stable elements can exist with two or more different neutron numbers in their nucleus. These are termed isotopes. Isotopes of the same element have the same number of protons in their nucleus (and hence orbital electrons, and hence chemical properties), but... 

From the foregoing discussion it appears that the unique spectral properties of polysilanes are due to the Si—Si bond acting as a chromophore, probably through the use of vacant d orbitals of the silicon atom (dw-dir double-bond character). While these spectral properties promise to be extremely useful in a study of numerous organic and inorganic polysilanes, further studies are necessary to determine the precise nature of the electronic excitations involved. 

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