Intermolecular forces are the forces of attraction and repulsion between interacting particles ( atoms and molecules ). This term does not include the electrostatic forces that exist between the two oppositely charged ions and the forces that hold atoms of a molecule together i.e. covalent bond.
According to NCERT, Covalent force can not be concluded as " intermolecular force " ! But we can see co-valent ( co-ordinate to be more specific) bond forming between NH3---->BF3 . Isn't covalent bond acting as intermolecular force here ?