Discussion Forum



1)

Consider the following complex ions P, Q , and R

$p= [FeF_{6}]^{3-},Q=[V(H_{2}O)_{6}]^{2+} and R= [Fe(H_{2}O)_{6}]^{2+}$

 the correct order of the complex ions. According in their spin-only magnetic moment values (in BM) IS


A) $R\lt Q\lt P$

B) $Q\lt R\lt P$

C) $R\lt P\lt Q$

D) $Q\lt P\lt R$

Answer:

Option B

Explanation:

Plan spin only magnetic moment $=\sqrt{N(N+2)}$ BM, when N is the number of unpaired elecrons. In presence of weak ligand (as H2O, Cl-, F-) there is no pairing of electrons, and electrons donated by ligands are filled in outer vacant orbitals 

 In presence of strong ligand

(as CN-, CO, NH3,en) electrons are paired and electrons from ligands are filled in available inner orbitals

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