The magnetic properties of transition metal compounds come from the presence of unpaired d-electrons. Here’s a explanation:
1. Types of Magnetism
- Paramagnetism
- Occurs when there are unpaired electrons in the d-orbitals.
- The compound is attracted to a magnetic field.
- Example: [Fe(H₂O)₆]³⁺
- Diamagnetism
- Occurs when all electrons are paired.
- The compound is slightly repelled by a magnetic field.
- Example: [Zn(CN)₄]²⁻
- Ferromagnetism (less common in compounds)
- Some compounds of iron, cobalt, and nickel show permanent magnetism due to aligned spins.
2. Factors Affecting Magnetic Properties
- Number of unpaired electrons: More unpaired electrons → stronger magnetism.
- High-spin vs Low-spin:
- High-spin complexes → more unpaired electrons → more paramagnetic.
- Low-spin complexes → fewer unpaired electrons → less paramagnetic.
- Type of ligand: Strong-field ligands can pair electrons → reduce magnetism.
In short:
- Transition metal compounds with unpaired electrons are paramagnetic.
- Those with all paired electrons are diamagnetic.
- Magnetism depends on d-electron configuration, spin state, and ligands.