Here's why:
* Strong electrostatic forces: Ionic compounds are formed by the electrostatic attraction between positively charged cations and negatively charged anions. These forces are very strong and hold the ions together in a rigid, crystalline lattice structure.
* High melting points: To break apart the strong ionic bonds and melt an ionic compound, a significant amount of energy is required. This is why ionic compounds generally have high melting points.
* Non-conductivity in solid state: In the solid state, the ions are locked in place within the lattice, preventing the flow of charge, making them poor conductors of electricity. However, they become excellent conductors when molten or dissolved in water, as the ions are free to move.
Exceptions: There are some exceptions to this general rule. For example, mercury(II) chloride (HgCl2) is a liquid at room temperature.
