Properties of Ionic Compounds

Exam code: 5070

Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Ionic compounds are usually solid at room temperature
They have high melting and boiling points
Ionic compounds are good conductors of electricity in the molten state or in solution
They are poor conductors in the solid state

Ionic substances have high melting and boiling points due to the presence of strong electrostatic forces acting between the oppositely charged ions
These forces act in all directions and a lot of energy is required to overcome them
The greater the charge on the ions, the stronger the electrostatic forces and the higher the melting point will be
- For example, magnesium oxide consists of Mg²⁺and O^2- so will have a higher melting point than sodium chloride which contains the ions, Na⁺ and Cl^-

For electrical current to flow there must be freely moving charged particles such as electrons or ions present
Ionic compounds are good conductors of electricity in the molten state or in solution as they have ions that can move and carry a charge
They are poor conductors in the solid state as the ions are in fixed positions within the lattice and are unable to move

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