Some important characteristics of ionic (or electrovalent) compounds are described below:
Hard and rigid:
Ionic (or electrovalent) compounds are hard and rigid due to strong columbic forces between the oppositely charged ions.
Ionic (or electrovalent) compounds have relatively high density. In ionic compounds, the ions are closely packed. This decreases the volume of the system, and as a result density is high.
High melting and boiling points:
Due to strong columbic force of an attraction the ions are bound to each other very firmly. As a result, the electrovalent or ionic solids have high melting and boiling points.
Lonic compounds dissolve easily in polar solvents such as, water but do not dissolve in non-polar organic solvents such as, benzene, carbon tetrachloride etc.
When dissolved in solvents like water or, when melted, the ionic compounds dissociate to give free ions. For example ,sodium chloride when dissolved in water gives sodium and chloride ions, viz.,
Solid ionic compounds do not conduct electricity. This is because the constituent ions are fixed to their positions in the solid state.
The ionic compounds however conduct electricity when dissolved in solvents like water or when melted. This is because the ions get free in the solution or in the melt. These free ions move freely in the solution melt, and conduct electricity.
In ionic compounds ions are arranged in a regular geometrical fashion. These orderly distributions of ions give characteristics geometrical shapes to the crystals of electrovalent (or ionic) compounds.