What is the difference between strong field and weak field ligands in LFT?

Weak-Field Ligands

• Make small splitting of metal d-orbitals.
• Usually give high-spin complexes (more unpaired electrons).
• Bond is mostly ionic.
• Examples: H₂O, OH⁻, Cl⁻

Strong-Field Ligands

• Make large splitting of metal d-orbitals.
• Usually give low-spin complexes (fewer unpaired electrons).
• Bond is more covalent.
• Examples: CN⁻, CO, NH₃

Simple Way to Remember

• Weak-field → high-spin → small splitting → more unpaired electrons
• Strong-field → low-spin → large splitting → fewer unpaired electrons