Why does solid CO2 become a gas at room temperature, but SiO2 does not?

Question

Hi, I'm currently learning about intermolecular forces and atomic radius, and this question has appeared:

 

Why does solid CO2 become a gas at room temperature, but SiO2 does not? 

Answer 1

CO2 is a linear compound (O=C=O) and is very non polar.  The only forces holding molecules together are the London Dispersion intermolecular forces.  SiO2 is actually a network solid where the Si is surrounded by 4 oxygen atoms forming a lattice network. The intermolecular forces in this configuration are rather significant, and so it is a solid at room temperature.  Further explanation would require an understanding of hybridization and bond strengths and lengths, which may be beyond the scope of this question.