Consider the molecular orbital diagram for a tetrahedral complex (based on Fig. 20.8) and the relevant d-orbital configuration, and show that the purple colour of [MnO₄]⁻ ions cannot arise from a ligand-field transition. Given that the wavenumbers of the two transitions in [MnO₄]⁻ are 18 500 and 32 200 cm⁻¹, explain how to estimate Δ_T from an assignment of the two charge-transfer transitions, even though Δ_T cannot be observed from a direct d-d transition.

Figure 20.8.

Transcribed Image Text:

Spherical environment d w Tetrahedral crystal field AT AT t₂ AT