Question

The correct order of the spin-only magnetic moment of metal ions in the following low spin complexes, $[V(CN{)}_6{]}^{4-},[Fe(CN{)}_6{]}^{4-},[Ru(N{H}_3{)}_6{]}^{3+},$ and $[Cr(N{H}_3{)}_6{]}^{2+}$, is :

• A. $V^{2+}>C{r}^{2+}>R{u}^{3+}>F{e}^{2+}$
• B. $V^{2+}>R{u}^{3+}>C{r}^{2+}>F{e}^{2+}$
• C. $C{r}^{2+}>V^{2+}>R{u}^{3+}>F{e}^{2+}$
• D. $C{r}^{2+}>R{u}^{3+}>F{e}^{2+}>V^{2+}$

Answer 1

Answer: (A)

Solution:- $(A)V^{2+}>C{r}^{2+}>R{u}^{3+}>F{e}^{2+}$
According to equations, all the complexes are low spin. No. of Complex Configuration unpaired electrons $[\begin{array}{lll}{\left[V(CN{)}_6\right]}^{4-}& t_{2g}^3{e}_g^0& 3\end{array}$
No. ot Complex Configuration unpaired electrons ${\left[V(CN{)}_6\right]}^{4-}{t}_{2g}^3{e}_g^0$
3
${{\left[Cr(NH{)}_3\right)}_6]}^{2+}{t}_{2g}^4{e}_g^0$
2
${\left[Ru{\left(N{H}_3\right)}_6\right]}^{3+}{t}_{2g}^5{e}_g^0$
1
${\left[Fe(CN{)}_6\right]}^{4-}{t}_{2g}^6{e}_g^0$
0