Question

How to tell strong ligand or weak ligand?

Answer 1

Answer:**ALL COMPLEX ARE FORMED WITH D BLOCK ELEMENTS ONLY DUE TO THE PRESENCE OF EMPTY D ORBITALS.**

Explanation:

STRONG FIELD LIGANDS (SFL ):

The ligands in which the donating ligands are (CARBON),(NITROGEN),(PHOSPHOROUS) then the complex is said to be a strong field ligand.

WEAK FIELD LIGANDS (WFL):

All other ligands except C,N,P donating are weak field ligands.

eg:$H_{2} O$ ,all halogens.

Exceptions:

--->$NH_{3}$  acts as WFL (weak field ligand) in the presence of  $Mn^{+2} ,Fe^{+2},Co^{+3}$ .

---> Also,(O) donating ligands acts as SFL in the presence of

   $Cr^{+3}, Cu^{+2}$

    eg: Oxalato($C_{2} O_{4}$), Water.

---->ALL ligands when bonded with 4d and 5d series D block elements it all acts as SFL.