Coordination Compounds — Chemistry STD 12 Science — Question

Spectro-chemical series is a series in which the ligands have been arranged in order of increasing magnitude of splitting they produce. The order is,
I– < Br^– < SCN^– < Cl^– < S^2– < F ^– < OH^– < C₂O₄^2– < H₂O < NCS^– < edta^4– < NH₃ < en < CN^– < CO
The ligand present on the R.H.S of the series are strong field ligand while L.H.S are weak field ligand. Also, strong field ligand cause higher splitting in the d- orbitals than weak field ligand.

	Weak field ligand	Strong field ligand
1.	They are formed when the crystal field stabilisation energy (Δ0) in octahedral complexes is less than the energy required for an electron pairing in a single orbital (p).	They are formed when the crystal field stabilisation energy (Δ0) is greater than the p.
2.	They are also called high spin complexes.	They are called low spin complexes.
3.	They are mostly paramagnetic in nature complex.	They are mostly diamagnetic or less paramagnetic than weak field.