Question

What do you understand by the term stability constant, K of a complex?

Answer 1

The stability constant (K), also known as the formation constant, is a measure of the stability of a coordination complex. It represents the equilibrium constant for the formation of a complex from its metal ion and ligands. The larger the value of K, the more stable the complex is, meaning the complex is less likely to dissociate into its components (metal ion and ligands).

For a general complex, the equilibrium can be represented as:

Metal ion + Ligands ⇌ Complex

The stability constant is given by:

K = `"[Complex]"/"[Metal ion][Ligands]"`

The higher the value of K, the more stable the complex, and hence, the less likely it will dissociate, leading to fewer metal ions in solution.