Why does silica have strong bonding that contributes to its melting point?

Silica, or silicon dioxide (SiO2), has a strong three-dimensional network structure formed entirely by covalent bonds. The numerous strong covalent bonds between the silicon and oxygen atoms require a significant amount of energy to break. This extensive interconnectivity in its structure leads to a high melting point because, to transition from a solid to a liquid, all of these bonds must be overcome.

Molecules in silica are not simple nor are they held together by weak intermolecular forces; rather, they exist in a rigid lattice comprising of many atoms, contributing significantly to its stability and high melting point. Moreover, while delocalized electrons are a characteristic of some metallic and covalent structures, silica does not rely on this feature to achieve its strength, focusing instead on its strong covalent bond network. Thus, the right choice highlights the importance of the strong covalent bonds in contributing to silica’s notable thermal properties.