Chemistry - Coordination Chemistry Question with Solution | TestHub

A coordination compound is a complex in which the number of ions or molecules attached to the central metal atom or ion is beyond the number possible on the basis of electrovalent or covalent bonding. The extra groups or ions are linked to the metal by coordination bonds in which the linked group (L) is the donor and the metal (M) is the acceptor, i.e., $M\leftarrow L$.

Coordination compounds are mainly of two types:

(i) Neutral compounds like $[Fe(CO{)}_5]$

(ii) Ionic compounds, which consist of ions in which at least one is a $\sigma$ complex ion. For example, $K_4[Fe(CN{)}_6]$.

Complex ion: A complex ion is an electrically charged radical that consists of a metal atom or ion surrounded by a group of ions or neutral molecules. For example, $[Cu(N{H}_3{)}_4{]}^{2+}$, $[Fe(CN{)}_6{]}^{3-}$.

Ligands are defined as molecules or ions having at least one pair of electrons for donation. Ligands are also known as Lewis bases.