The Ionic
crystals. Positive and
negative ions are supported in the Crystal network for electrostatic
attractions. Because the forces are strong, ionic substances have high melting
points. Ionic crystals are hard and brittle. Due to the movement of an ion on
another plane, ions with the same charge repel each other. The crystal breaks
into pieces; these are good conductors of electricity when molten or in
solution (Mortimer, 1983).