709 results about "Valence band" patented technology

In solids, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature. The valence electrons are bound to individual atoms, as opposed to conduction electrons, which can move freely within the atomic lattice of the material. On a graph of the electronic band structure of a material, the valence band is located below the conduction band, separated from it in insulators and semiconductors by a band gap. In metals, the conduction band has no energy gap separating it from the valence band.F To understand the concept of a valence band, it is important to consider the atomic structure of a metal first. For example lithium atoms with electronic configuration 1s²2s¹ can form only one covalent bond. However, when forming a bulk metal, Li atoms come to a resonance structure by taking 1 electron from its neighbouring Li atom and the resultant electronic configuration becomes 1s²2s¹2p¹. As a result of this electron sharing, its neighbouring Li atom loses an electron and comes to an electronic configuration of 1s². The Li atoms now gain the capability to form two covalent bonds thus can form a bulk metal.