A crystal in which the basic units are noble gases or molecules, such as benzene or methane, that do not have a permanent dipole moment, with the basic units held together by the van der Waals’ force. As the bonds associated with the van der Waals’ force are much weaker than the bonds in metals, covalent crystals, and ionic crystals, the melting points of molecular crystals are small and they have small cohesion energies.