The ionic compounds form crystals. Ionic compounds form crystal lattice rather than amorphous solids.
Although molecular compounds form crystals, they frequently take other forms plus molecular crystals typically are softer than ionic crystals.
• The ionic bond is non-directional. This is because each ion is surrounded by oppositely charged iotns uniformly distributed all around the ion.
• Ionic solids are good insulators.
• Ionic compounds conduct electricity when they are dissolved in water or in molten state.
• Ionic compounds are hard and brittle.
• Ionic compounds have higher enthalpies of fusion and vaporization than molecular compounds.
• Ionic compounds have high melting points and high boiling points.