Ionic compound :

• Ionic compounds are those compounds that are formed by the gain and loss of electrons by an element.
• these are mostly found in the crystalline state consisting of orderly 3-dimensional arrangement (3D) of cations and anions held together by Columbic interaction energy.
• A qualitative measure of the stability of ionic compounds is provided by their enthalpy of lattice  formation , which makes them good conductors of electricity.
• examples MgCl2 , here Mg(magnesium) is a cation which loses its 2 electrons to become stable where as chlorin is an anion and acceptor of electron hence the ionic compound form.

Covalent compound :

• covalent compounds are those compounds which are form by the sharing of electron pair.
• these counpounds exist in both crystalline and amorous forms like diamond and graphite respectively.
• they are held together by a weak vander waal force of interaction which makes them bad conductors of electricity.
• these compounds are comparatively less stable than ionic compounds because of weak forces.
• example; CO2 (carbon dioxide),NH3(ammonia),H2O(water).

hence above are all the major difference between the ionic and the covalent         compounds.