A metalloid is a chemical element  that has properties that are in between or a mixture of those of metals and nonmetals and is consequently difficult to classify unambiguously as either a metal or a nonmetal. There is no standard definition of a metalloid, nor is there agreement as to which elements are appropriately classified as such. Despite this lack of specificity the term remains in use in chemistry literature.The six elements commonly recognised as metalloids are B, Si, Ge, As, Sb, Te

 A semimetal is a material with a very small overlap between the bottom of the conduction band and the top of the valence band. A semimetal thus has no band gap and a negligible density of states at the fermi level. A metal, by contrast, has an appreciable density of states at the Fermi level because the conduction band is partially filled.