1. The structural units of an ionic crystals are cations and anions. They are bound together by strong Na electrostatic attractive forces.
2. To maximize the attractive force, cations are surrounded by as many anions as possible and vice versa.
3. Ionic crystals possess definite crystals structure.
4. Many solids are cubic close packed.
Characteristics
1. Ionic solids have high melting points.
2. These solids do not conduct electricity, because the ions are fixed in their lattice positions.
3. They do not conduct electricity in molten state (or) when dissolved in water, because the ions are free to move in the molten state or solution.
4. They are hard as only strong external force can change the relative positions of ions.
5. Example – The arrangement of Na and Cl ions in NaCI crystal.
