Molecular solids

• The larger the size of the molecule, the greater the attractive forces (induced dipole-induced dipole)
• Usually, simple molecules are gases at room temperature, but some covalently bonded molecules have strong enough attractive forces to form solids at room temperature
• Iodine is a solid at room temperature because there are strong bonds inside molecules, weak intermolecular forces between molecules
• Molecular crystals are soft because they are held together by weak Van Der Waal's forces (id-id)
• They have low melting/boiling points because there are weak intermolecular id-id forces between iodine molecules that are broken, so it requires less energy to break them
• They are non conductors in any state because they are neutral molecules so they do not have any free moving delocalised electrons or ions that conduct electricity
• They are virtually insoluble in water because they can't form hydrogen bonds with water so they are insoluble in water