Chemical Bonding and Molecular Structure
8.0 Coordinate Bond
8.0 Coordinate Bond
It is a special type of covalent bond in which both the shared electrons are contributed by one atom only.
It may be defined as “a covalent bond in which both electrons of the shared pair are contributed by one of the two atoms”. Such a bond is also called as dative bond.
A coordinate or a dative bond is established between two such atoms, one of which has a complete octet and possesses a pair of valence electrons while the other is short of a pair of electrons.
This bond is represented by an arrow $\left( \to \right)$ pointing towards acceptor atom.
The atom which contributes electron pair is called the donor while the atom which accepts it is called acceptor.
The compound consisting of the coordinate bond is termed coordinate compound. Some examples of coordinate bond formation are given below:
$1.$ Formation of ammonium ion:
Hydrogen ion $(H^+)$ has no electrons and thus accepts a lone pair donated by nitrogen.
$2.$ Formation of $CO$:
Carbon has four valency electrons and oxygen has six. They combine to form two double bond and a coordinate bond as to achieve their octet completed.
