Chapter 23, Problem 23.94P

Interpretation Introduction

Interpretation:

The colour of the weaker field ligand ${\left[{\text{MQ}}_{\text{6}}\right]}^{\text{2+}}$ has to be identified.

Concept introduction:

The fact that colour depends on the ligand allows us to create a spectrochemical series, which ranks the ability of a ligand to split $\text{d-orbital}$ energies.

The relative magnitude of $\Delta$ for a series of octahedral complexes of a given metal ion.  As $\Delta$ increases, higher energies (shorter wavelengths) of light must be absorbed to excite electrons.

The spectrochemical series is

  $I^{-}<C{l}^{-}<F^{-}<O{H}^{-}<H_{2}O<SC{N}^{-}<en<N{O}_2^{-}<C{N}^{-}<CO$

Relationships on an artist’s colour wheel in which complementary colors are wedges opposite each other.

Figure 1