The formation of the dative covalent (or coordinate covalent) bond

The formation of a dative covalent bond, also known as a coordinate covalent bond, occurs when one atom donates both of its electrons to another atom to form a covalent bond. This type of bond is also known as a “dative” bond because the electrons are donated by one atom to another, rather than being shared equally.

For example, in the case of H3O+ (hydronium ion) and NH4+ (ammonium ion), the dative covalent bond forms between the oxygen atom in H3O+ and the nitrogen atom in NH4+. The electron diagram for this formation is as follows:

H3O+:

 
   O
  / \
 H   H

NH4+:

    N
   / \
  H   H
  |   |
  H   H

The oxygen atom in H3O+ has a lone pair of electrons, while the nitrogen atom in NH4+ has a partially filled outer shell. When these two atoms come into close proximity, the oxygen atom donates one of its lone pair of electrons to the nitrogen atom, forming a covalent bond. This results in the formation of H3O+ NH4+ molecule.

The electron diagram for this molecule is:

H3O+ NH4+ :

     
   O
  / \
 H   H
     |
     N
    / \
   H   H
   |   |
   H   H

In this case, the oxygen atom donates one of its electrons to the nitrogen atom, forming a dative covalent bond. As a result, the nitrogen atom now has a full outer shell of electrons, and the oxygen atom has a single lone pair of electrons.

It’s important to note that this type of bond formation can occur between other types of atoms and molecules as well, not just H3O+ and NH4+. Dative covalent bond formation can be observed in many chemical reactions and is an important concept in understanding the behavior of molecules and their interactions with other molecules.