Correct order of spin only magnetic moment of the following complex ions is:
(Given At.no. Fe: 26, Co:27)
(Given At.no. Fe: 26, Co:27)
- $ [FeF_6]^{3−} >[Co(C_2O_4)_3]^{3−}>[CoF_6]^{3−}$
- $ [FeF_6]^{3−}>[CoF_6]^{3−}>[Co(C_2O_4)_3]^{3−} $
- $ [Co(C_2O_4)_3]^{3−}>[CoF_6]^3−>[FeF_6]^{3−} $
- $ [CoF_6]^{3−}>[FeF_6]^{3−}>[Co(C_2O_4)_3]^{3−} $
The Correct Option is B
Solution and Explanation
The spin-only magnetic moment depends on the number of unpaired electrons.
For [FeF$_6$]$^{3-}$, Fe$^{3+}$ has 5 unpaired electrons, resulting in the highest magnetic moment.
For [CoF$_6$]$^{3-}$, Co$^{3+}$ in a weak field ligand (fluoride) has 4 unpaired electrons.
For [Co(C$_2$O$_4$)$_3$]$^{3-}$, Co$^{3+}$ in a strong field ligand (oxalate) has 0 unpaired electrons.
Thus, the order of magnetic moment is [FeF$_6$]$^{3-}$ $>$ [CoF$_6$]$^{3-}$ $>$ [Co(C$_2$O$_4$)$_3$]$^{3-}$.
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Concepts Used:
Coordination Compounds
A coordination compound holds a central metal atom or ion surrounded by various oppositely charged ions or neutral molecules. These molecules or ions are re-bonded to the metal atom or ion by a coordinate bond.
Coordination entity:
A coordination entity composes of a central metal atom or ion bonded to a fixed number of ions or molecules.
Ligands:
A molecule, ion, or group which is bonded to the metal atom or ion in a complex or coordination compound by a coordinate bond is commonly called a ligand. It may be either neutral, positively, or negatively charged.