- The ions in an ionic crystal are held together by strong
ionic bonds or electrostatic forces of attraction.
- A large amount of heat is needed to break these strong
bonds, so a very high temperature is required. Therefore, ionic
compounds have high melting and boiling points.
- The melting points of ionic compounds depend on the
strength of their ionic bonds. The bigger the charges of the positive
and negative ions, the stronger are the ionic bonds and the higher the
- Ionic compounds do not conduct electricity when
- When they are heated strongly, they melt at a high
temperature. The molten compound then conducts electricity.
- Ionic compounds also conduct electricity when they dissolve
in water. This is because the ions can move in the molten state or
when dissolved in water.
- It is the moving ions that carry the electric
current. In the solid state, the ions cannot move, so the current
[ Formation of ionic compound ] [ Formation of covalent compound ]