Hey,

Ionic bonds are formed due to  the mutual attraction between oppositely charged ions, while a Covalent Bond gets formed due to the sharing of electrons between nuclei. Ionic bonds are more stronger than covalent bonds due to the columbic attraction between ions of opposite charges.

Ionic bond is more stable, given the fact that the hydration energy of the given compound is less than its lattice energy. In terms of lattice energy, the ionic solid is much more stable than relatively more covalent compound.

Hope it helps.