Question

What is spectrochemical series? Explain the difference between aweak field ligand and a strong field ligand.

Answer 1

A spectrochemical series is the arrangement of common ligands inthe increasing order of their crystal-field splitting energy (CFSE)values. The ligands present on the R.H.S of the series are strongfield ligands while that on the L.H.S are weak field ligands. Also,strong field ligands cause higher splitting in the d orbitalsthan weak field ligands.

I− < Br⁻ < S²⁻ <SCN⁻ < Cl⁻< N₃ <F⁻ < OH⁻ < C₂O₄²⁻∼ H₂O < NCS⁻ ∼ H⁻< CN⁻ < NH₃ < en ∼ SO₃²⁻< NO₂⁻ < phen < CO