Which type of crystalline solid is composed of individual molecules held together by intermolecular forces?
Molecular solids
Covalent or network solids
Ionic solids
Metallic solids
Molecular solids are composed of individual molecules held together by intermolecular forces such as van der Waals forces, hydrogen bonding, or dipole-dipole interactions. These forces are relatively weak compared to the chemical bonds within the molecules themselves. As a result, molecular solids tend to have lower melting and boiling points than covalent or ionic solids.
Examples of molecular solids include solid CO2 (dry ice), solid iodine, and many pharmaceuticals. Because of their relatively weak intermolecular forces, molecular solids tend to be soft and brittle and are typically poor conductors of heat and electricity.