Spectrochemical series

Definition

The spectrochemical series is an empirically derived list of ligands ordered by the magnitude of the crystal field splitting energy ($\Delta$) they produce when coordinating to a metal ion. Ligands at the high end of the series cause a larger splitting of d-orbital energies, resulting in stronger field effects.

5 Must Know Facts For Your Next Test

1. Ligands are ranked from weak-field to strong-field in the spectrochemical series.
2. Common weak-field ligands include $I^-$ and $Br^-$, while strong-field ligands include $CN^-$ and $CO$.
3. The position of a ligand on the spectrochemical series affects the color and magnetic properties of coordination compounds.
4. Strong-field ligands tend to produce low-spin complexes, while weak-field ligands tend to produce high-spin complexes.
5. The spectrochemical series helps predict whether a complex will undergo high or low spin configurations based on ligand strength.

Review Questions

• How does the position of a ligand in the spectrochemical series affect the electronic configuration of a metal center?
• Name two examples each of weak-field and strong-field ligands according to the spectrochemical series.
• Why are strong-field ligands associated with low-spin complexes?

Related terms

Crystal Field Splitting: The difference in energy between d orbitals in a metal complex due to ligand interactions.

High-Spin Complex:

A coordination compound where electrons occupy higher-energy orbitals first, resulting in more unpaired electrons.

Low-Spin Complex:

A coordination compound where electrons pair up in lower-energy orbitals first, resulting in fewer unpaired electrons.