1. High melting and boiling points: Ionic compounds have strong electrostatic attractions between their oppositely charged ions. This strong attraction requires a lot of energy to overcome, leading to high melting and boiling points.

2. Good conductors of electricity when molten or dissolved in water: When melted or dissolved in water, the ions become free to move. This mobility allows them to carry an electric current, making the molten or dissolved compound a good conductor. Solid ionic compounds are generally poor conductors because the ions are fixed in a rigid lattice structure.

3. Generally soluble in polar solvents: Ionic compounds are often soluble in polar solvents, such as water, because the polar solvent molecules can surround and interact with the ions, breaking the ionic bonds and allowing the compound to dissolve. They are less soluble in nonpolar solvents.