What can be inferred from the magnetic moment values of the following complex species?
Example | Magnetic Moment $(BM)$ |
$K _{4}\left[ Mn ( CN )_{6}\right.$ | $2.2$ |
$\left[ Fe \left( H _{2} O \right)_{6}\right]^{2+}$ | $5.3$ |
$K _{2}\left[ MnCl _{4}\right]$ | $5.9$ |
Magnetic moment $\left( \mu \right)$ is given as $\mu=\sqrt{n(n+2)}$
For value $n=1,$ $\mu=\sqrt{1(1+2)}=\sqrt{3}=1.732$
For value $n=2,$ $\mu=\sqrt{2(2+2)}=\sqrt{8}=2.83$
For value $n=3,$ $\mu=\sqrt{3(3+2)}=\sqrt{15}=3.87$
For value $n=4,$ $\mu=\sqrt{4(4+2)}=\sqrt{24}=4.899$
For value $n=5,$ $\mu=\sqrt{5(5+2)}=\sqrt{35}=5.92$
$(i)$ $K _{4}\left[ Mn ( CN )_{6}\right]$
For in transition metals, the magnetic moment is calculated from the spin-only formula. Therefore,
$\sqrt{n(n+2)}=2.2$
We can see from the above calculation that the given value is closest to $n=1$. Also, in this complex, Mn is in the $+2$ oxidation state. This means that $Mn$ has $5$ electrons in the $d$ orbital.
Hence, we can say that $CN ^{-}$ is a strong field ligand that causes the pairing of electrons.
$(ii)$ $\left[ Fe \left( H _{2} O \right)_{6}\right]^{2+}$
$\sqrt{n(n+2)}=5.3$
We can see from the above calculation that the given value is closest to $n=4$. Also, in this complex, $Fe$ is in the $+2$ oxidation state. This means that $Fe$ has $6$ electrons in the $d$ -orbital
Hence, we can say that $H _{2} O$ is a weak field ligand and does not cause the pairing of electrons.
$(iii)$ $K _{2}\left[ MnCl _{4}\right]$
$\sqrt{n(n+2)}=5.9$
We can see from the above calculation that the given value is closest to $n=5$. Also, in this complex, $M n$ is in the $+2$ oxidation state. This means that $M n$ has $5$ electrons in the $d$ -orbital.
Hence, we can say that $Cl ^{-}$ is a weak field ligand and does not cause the pairing of electrons.
For the ions $Zn ^{2+}, \,Ni ^{2+}$ and $Cr ^{3+}$ which among the following statements is correct ?
(Atomic number of $Zn =30,\,Ni =28$ and $Cr =24$ )
Assertion : Transition metals are good catalysts.
Reason : $V_2O_5$ or $Pt$ is used in the preparation of $H_2SO_4$ by contact process.
Chloro compound of vanadium has only spin magnetic moment of $1.73\,BM$ . This vanadium chloride has the formula :- (at no. of $V = 23$ )
The colour of copper sulphide is
Find the species having the magnetic moment value of $5.92\ BM$