Provide an example of the strong and weak field ligands in the ligand field theory.

In ligand field theory, strong field ligands cause greater splitting of d-orbitals than weak field ligands.

Strong field ligands are those that cause a large energy difference between the d-orbitals of the metal ion. This is because they are able to interact strongly with the metal ion and cause a greater repulsion between the electrons in the d-orbitals. Examples of strong field ligands include cyanide (CN-), carbon monoxide (CO), and ammonia (NH3).

On the other hand, weak field ligands cause a smaller energy difference between the d-orbitals of the metal ion. This is because they are not able to interact as strongly with the metal ion and cause less repulsion between the electrons in the d-orbitals. Examples of weak field ligands include water (H2O), chloride (Cl-), and hydroxide (OH-).

The strength of a ligand can be determined by its ability to donate electrons to the metal ion, which is related to its electronegativity and the size of its donor atom. Generally, ligands with small donor atoms and high electronegativity are strong field ligands, while ligands with larger donor atoms and lower electronegativity are weak field ligands.

A-Level Chemistry Tutor Summary: In ligand field theory, strong field ligands, like cyanide (CN-), carbon monoxide (CO), and ammonia (NH3), cause a large energy split between d-orbitals in metal ions, due to their strong interaction and electron repulsion. Weak field ligands, such as water (H2O), chloride (Cl-), and hydroxide (OH-), have a smaller split because of their weaker interaction. The ligand's strength depends on its electron-donating ability, linked to electronegativity and donor atom size.