Why is [Ti(H2O)6)] 3+ violet in colour ?
In [Ti(H2O)6)]3+, Ti3+ ion has only one electron in 3d-orbital. The electron occupies the orbital of the lowest energy, i.e., any one of the degenerate t2g orbitals. The violet/purple colour of [Ti(H2O)6)]3+ ion is due to absorption of blue-green light and transition of electron of the t2g orbitals to one of the degenerate eg ortibals. The absorption spectrum of [Ti(H2O)6)]3+ reveals that the d-d transition occurs with a single broad peak.