Metallic bonding and band theory

Metallic structure and bonding are characterized by delocalized valence electrons, which are responsible for the high electrical conductivity of metals. This contrasts with ionic and covalent bonding in which the valence electrons are localized on particular atoms or ions and hence are not free to migrate through the solid. The physical data for some solid materials are shown in Table 4.3.1. 

The band theory of solids has been developed to account for the electronic properties of materials. Two distinct lines of approach will be described. 

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