Top topic this week
Back to FAQs
Related FAQs
Frequently Asked Question
Questions asked by users might not always be phrased in the clearest way.
Choose the coordination complex from below that would present with the least intense peaks in the UV-Vis spectrum. [1 mark] [ti(h2o)6]2+ [v(h2o)6]2+ [mn(h2o)6]2+ [ni(h2o)6]2+
Accepted Answer
The coordination complex [Mn(H2O)6]2+ would present with the least intense peaks in the UV-Vis spectrum.
Here's why:
UV-Vis Spectroscopy and d-d Transitions: UV-Vis spectroscopy probes electronic transitions, particularly those involving d-orbitals in transition metal complexes. The intensity of the peaks is related to the allowedness of these transitions.
Selection Rules: The d-d transitions in coordination complexes are generally
forbidden
by the Laporte rule, which states that transitions between orbitals with the same parity (symmetry) are forbidden. However, some factors can make these transitions weakly allowed.
Mn(II) d-Electron Configuration: Mn(II) has a d5 configuration (3d5). In a high spin complex like [Mn(H2O)6]2+, all five d-orbitals are individually occupied. This leads to minimal d-d transitions because there are no empty d-orbitals to easily promote electrons to.
Other Complexes: The other complexes have d-electron configurations that allow for more d-d transitions, making their UV-Vis spectra more intense.
In summary, [Mn(H2O)6]2+ exhibits the least intense UV-Vis peaks due to its d5 electronic configuration and the resulting limited d-d transition possibilities.
Articles you might like