Why do ionic compounds conduct electricity only when molten or in solution?

Ionic compounds consist of a lattice structure where ions are arranged in a regular pattern and held together by strong electrostatic forces. In the solid state, these ions are not free to move because they are fixed in place within the lattice structure. This lack of mobility prevents solid ionic compounds from conducting electricity.

However, when ionic compounds are melted or dissolved in a solvent such as water, the rigid lattice breaks apart. This process allows the ions to become free to move. The movement of these charged ions enables the flow of electric current, making molten or dissolved ionic compounds capable of conducting electricity.

This property is why ionic compounds conduct electricity only when they are in either molten form or in solution, as it is the mobility of the ions that is crucial for conducting electrical current.