Final answer:
Ionic and network covalent solids have higher melting and boiling points than most molecular compounds due to the type of bonding present in these solids.
Step-by-step explanation:
Ionic and network covalent solids possess significantly higher melting and boiling points compared to most molecular compounds due to the type of bonding present in these solids.
In ionic compounds, the ions are held together by strong ionic bonds in a 3D array of crystal lattices. These strong bonds require a high amount of energy to break, resulting in high melting and boiling points.
Network covalent solids, on the other hand, consist of a 3D network of covalent bonds, such as diamond or silicon dioxide. Breaking these covalent bonds requires a large amount of energy, resulting in higher melting points compared to ionic compounds.