An ionic compound is formed when there is a reaction between the elements

An ionic compound is formed when there is a reaction between the elements whose ions are electrostatically attracted.

Explanation:

The ionic compounds form crystalline networks with ionic bonding. Electrostatic attraction is a very strong bond that is very difficult to break. The stability of the ionic compound depends on the lattice energy, the higher it is, the more stable the compound is and the lattice energy is that which is released in the formation. At room temperature they are always in a solid state, because the bonds are very close and as stated before, they are difficult to break (providing a lot of energy)