What is the relationship between observed colour of the complex and the wavelength of light absorbed by the complex?
What is the relationship between observed colour of the complex and the wavelength of light absorbed by the complex?
When the light falls on the complex, some part of it is absorbed. Higher the crystal field splitting energy, lower will be the wavelength absorbed by the complex. The observed colour of the complex is the clour generated from the wavelength left over.
e.g., if the green light is absorbed, the complex appears red.
In terms of crystal field theory, suppose there is an octahedral complex with empty eg level and unpaired electrons in the t2g level in ground level. If the unpaired electron absorbs light corresponding is a blue-green region, it will excite to eg level and the complex will appear violet in colour.
In absence of ligand, crystal field does not occur and the substance is colourless.
e.g., anhydrous CuSO4 is white, but CuSO4.5H2O is blue in colour.
When the light falls on the complex, some part of it is absorbed. Higher the crystal field splitting energy, lower will be the wavelength absorbed by the complex. The observed colour of the complex is the clour generated from the wavelength left over.
e.g., if the green light is absorbed, the complex appears red.
In terms of crystal field theory, suppose there is an octahedral complex with empty eg level and unpaired electrons in the t2g level in ground level. If the unpaired electron absorbs light corresponding is a blue-green region, it will excite to eg level and the complex will appear violet in colour.
In absence of ligand, crystal field does not occur and the substance is colourless.
e.g., anhydrous CuSO4 is white, but CuSO4.5H2O is blue in colour.
