Explian givin appropriate structural information why CO2 is a gas at room temperature while.......?

Question

SiO2 is a high melting point solid?

Answer 1

CO2 has a simple molecular structure, and the only attractive forces between the molecules are vdW ones. Thus only a small amount of energy is required to break them on melting.

SiO2 has a giant covalent structure, in which all the covalent bonds have to be loosened on melting. This requires a great deal of energy.