Permanganate Colour

Permanganate is an inorganic compound with the chemical formula KMnO4. It is a strong oxidizing agent and has a deep purple color in its solid form.

In solution, permanganate ion (MnO4-) exhibits a characteristic intense purple color due to its electronic transitions. Specifically, the color arises from the splitting of the d-orbitals of the manganese atom in the central MnO4- ion as it undergoes d-d transitions.

In more detail, when permanganate ion is dissolved in water, the oxygen atoms surrounding the manganese atom create a crystal field that splits the five d-orbitals into two groups - three orbitals of higher energy (the eg set) and two orbitals of lower energy (the t2g set). The energy difference between these two sets corresponds to the wavelength of light that is absorbed by the permanganate ion, resulting in a visible purple color.

The intensity and shade of the color can be influenced by several factors, including the concentration of the permanganate solution, the pH of the solution, and the presence of other ions or organic compounds that may interact with the permanganate ion. For example, acidic solutions tend to have a stronger and more vibrant purple color, while basic solutions can cause the permanganate ion to decompose and lose its color.