Question

why do ionic compounds have high melting points​

Answer 1

This is because of the strong attractive electrostatic forces holding the oppositely charged ions together and a large number of ionic bonds in the crystal lattice. These require a lot of thermal energy to overcome and hence have both high melting and boiling points.

Answer 2

They have high melting points ..also boiling points because a considerable amount of energy is required to break the strong inter ionic attraction ...(they have strong intermolecular attraction)