Question

in coordinate bond the donar atom must be essentially to contain its valency shell an orbital​

Answer 1

Ammonium ions, NH4+, are formed by the transfer of a hydrogen ion from the hydrogen chloride to the lone pair of electrons on the ammonia molecule. ... Once the ammonium ion has been formed it is impossible to tell any difference between the dative covalent and the ordinary covalent bonds.

Covalent Bonds