Answer
The color of coordination complexes mainly originate from the two sources:
(1) d-d transition: In case of octahedral complex, d-d transition means the transition of electron from the t2g to the eg level. The energy required for this transition is equal to the crystal field splitting. The d-d transition can occur only in complexes of transition of metal ion with incomplete d-shells.
In general, if the transition requires higher energy, then the corresponding transmitted light will be of lower energy, and if transition requires lower energy, then the corresponding transmitted light will be of higher energy.
(2) Charge transfer transition: There are many compounds where between metal and ligand, one is highly oxidizing and the other is highly reducing. In such case, there may occur charge transfer (i.e. electron transfer) from the reducing partner to the oxidizing partner. This type of transition is called charge transfer transition.
Work Step by Step
The color of coordination complexes mainly originate from the two sources:
(1) d-d transition: In case of octahedral complex, d-d transition means the transition of electron from the t2g to the eg level. The energy required for this transition is equal to the crystal field splitting. The d-d transition can occur only in complexes of transition of metal ion with incomplete d-shells.
In general, if the transition requires higher energy, then the corresponding transmitted light will be of lower energy, and if transition requires lower energy, then the corresponding transmitted light will be of higher energy.
(2) Charge transfer transition: There are many compounds where between metal and ligand, one is highly oxidizing and the other is highly reducing. In such case, there may occur charge transfer (i.e. electron transfer) from the reducing partner to the oxidizing partner. This type of transition is called charge transfer transition.
