Electronic transitions of a color will occur by the absorption of ultraviolet and visible radiation. Though transitions are attainable, solely the subsequent varieties has to allow.
–n → π* and π → π*
Electronic Transitions of a color
A σ → σ* transition takes place once a bonding σ –electron is happy to associate degree antibondingσ –orbital, i.e. σ*. This type of transition needs a really great deal of energy as σ – electrons area unit terribly tightly bonded. Hence the compounds like saturated hydrocarbons that don’t have any π or σ electrons might bear solely σ → σ* transitions.
However, these transitions don’t occur by fascinating within the normal ultraviolet region.
How it works
Transition parts area unit sometimes characterized by having d orbitals. Currently once the metal isn’t guaranteed to anything, these d orbitals area unit degenerate. Which means that all of them have an equivalent energy. However once the metal starts bonding with alternative ligands, this changes. Thanks to the various symmetries of the d orbitals and therefore the inductive effects of the ligands on the electrons, the d orbitals split apart and become non-degenerate (have totally different energy levels).
Hope this will help you getting the idea of Electronic transitions of color constitutions.