A property of ionic compounds is that they are soft and brittle. When stress is applied to an ionic compound, the layers of ions can shift, causing like charges to come into contact, which results in repulsion and causes the material to break.
While ionic compounds do conduct electricity when dissolved in water or molten (because the ions are free to move), they do not conduct electricity in their solid state. Moreover, ionic compounds typically have high boiling and melting points, not low.