Question

What is hydrate isomerism? Explain with an example?

Answer 1

Hydrate isomerism:

• “This form of isomerism is known as ‘hydrate isomerism’ because water is involved as a solvent.”
• This isomerism is a type of ionization isomerism in which the compounds differ by the number of solvent molecules directly bonded to the metal ion. They can act as ligands and as free molecules in the lattice.

Example of Hydrate isomerism:

• Hexaaquachromium(III)chloride$\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]{\mathrm{Cl}}_3$ : violet-colored
• Pentaaquachloridochromium(III) chloridemonohydrate$\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_5\mathrm{Cl}\right]{\mathrm{Cl}}_2.{\mathrm{H}}_2\mathrm{O}$ : blue-green in color
• Tetraaquadichloridochromium(III) chloridedihydrate$\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_4{\mathrm{Cl}}_2\right]\mathrm{Cl}.2{\mathrm{H}}_2\mathrm{O}$: dark green in color
• The above three complexes are examples of hydrate isomerism.