The main point of difference between electrovalent ionic and covalent compounds are summed up in table below :
Electrovalent Ionic Compounds :
(i) They are formed as a result of complete transfer of electrons (gain or loss) from one atom to another.
(ii) These compounds are generally solids.
(iii) They are made up of ions with powerful electrostatic forces of attraction.
(iv) They have generally high melting and boiling points.
(v) They are generally soluble in polar solvents like water and insoluble inorganic solvents.
(vi) Ionic compounds conduct electricity in the molten or dissolved state.
(vii) Ionic compounds are non-directional and they do not show isomerism.
(viii) These compounds undergo ionic reactions which are very fast, almost instantaneous.
Covalent Compounds :
1.They are formed by sharing of electrons between two atoms.
2.(ii) These compounds may be solids, liquids or gases.
(iii) They are made up of molecules held together by weak van der Waals forces of attraction.
(iv) They have generally low melting and boiling points.
(v) Covalent compounds are generally soluble in non-polar solvents such as benzene and insoluble in polar solvents.
(vi) Covalent compounds are generally bad conductors of electricity.
(vii) Covalent compounds are rigid and directional. They show isomerism.
(viii) These compounds undergo molecular reactions which are very slow.