Diamond is considered as an insulator because

Step-by-step solution

Diamond is an allotrope of carbon where each carbon atom is sp ³ hybridized and forms four strong covalent bonds with neighboring carbon atoms. This structure results in a rigid, three-dimensional network. In terms of band theory, the valence electrons are tightly bound in these covalent bonds. The energy required to excite an electron from the valence band to the conduction band is the forbidden energy gap (band gap). For diamond, this band gap is approximately 5.5 eV, which is significantly large. Because of this