Question

Define a coordinate bond and give the conditions for its formation.

Answer 1

A coordinate bond is defined as a bond between two atoms that is formed by sharing of a pair of electrons donated entirely by one of the two combining atoms.
Conditions for formation of a coordinate bond:

1. At least one lone pair of electrons should be present in one of the combining atoms. For example, in ammonia molecule, nitrogen atom has a lone pair of electrons that is available for donation to another atom.

2. Second atom should lack at least a pair of electrons. For example, Hydrogen ion (H⁺) does not have electron. It is deficient of two electrons.