Chemistry – Atoms, elements and compounds - Giant covalent structures | e-Consult

Silicon(IV) oxide (\$SiO_2\$) is a poor conductor of electricity because its giant covalent structure contains no free electrons. In a conductor, electrons are delocalised and can move freely throughout the material, carrying an electrical charge.

In \$SiO_2\$, all the electrons are involved in covalent bonding, forming strong bonds between the silicon and oxygen atoms. These electrons are not free to move and therefore cannot carry an electrical current. The strong covalent network prevents the movement of electrons, resulting in electrical insulation.