MCQ
Which among the following is a paramagnetic complex?
$($At. No. $Mo = 42, Pt = 78)$
- A$[Co(NH_3)_6]^{3+}$
- B$[Pt(en)Cl_2]$
- ✓$[CoBr_4]^{2-}$
- D$Mo(CO)_6$
✓
Answer
Correct option: C.
$[CoBr_4]^{2-}$
c
Magnetic Moments (spin only)- $\sqrt{n(n+2)}$
Magnetic Moments (spin only)- $\sqrt{n(n+2)}$
where $n=$ number of unpaired electron.
Number of unpaired $e^{-} s$ and corresponding magnetic moments
$1 \rightarrow 1.7$
$2 \rightarrow 2.8$
$3 \rightarrow 3.9$
$4 \rightarrow 4.9$
$5 \rightarrow 5.9$
since $B r^{-}$ is a weak feild ligand, so electrons in $C o^{2+}$ will not pair up.
the complex has $3$ unpaired electrons leaving it paramagnetic in nature.
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