* Bonding: SiO2 has a network covalent structure. This means silicon and oxygen atoms are linked together in a giant, three-dimensional network of strong covalent bonds. CO2, on the other hand, is a simple molecule with weak intermolecular forces (van der Waals forces) between molecules.
* Strength of Bonds: Covalent bonds are much stronger than van der Waals forces. To break the network of covalent bonds in SiO2, a lot more energy is required than to overcome the weak intermolecular forces in CO2.
Boiling Point:
* SiO2: 2230 °C (4028 °F)
* CO2: -78.5 °C (-109.3 °F)
In short: The strong covalent bonding in SiO2 makes it extremely difficult to break apart, leading to its very high boiling point. CO2's simple molecular structure and weak intermolecular forces result in a much lower boiling point.
