(i) \(\mathrm{K}\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_2\left(\mathrm{C}_2 \mathrm{O}_4\right)_2\right] \cdot 3 \mathrm{H}_2 \mathrm{O}\)
IUPAC name is :
potassiumdiaquadioxalatochromate(III) hydrate.
Coordination number \(=6\)
Oxidation state of \(\mathrm{Cr}: x+0+2(-2)=-1\)
\(\therefore x=+3\)
Shape is octahedral
Electronic configuration of
\(\mathrm{Cr}^{3+}=3 d^3=t_{2 \mathrm{~g}}^3 e_{\mathrm{g}}^0\).
Magnetic moment,
\(\mu=\sqrt{n(n+2)}=\sqrt{3 \times 5}=\sqrt{15} \text { BM. }\)
\(=3.87 \mathrm{BM}\)
(ii) \(\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2\)
IUPAC name is :
pentaamminechloridocobalt (III) chloride
Coordination number of \(\mathrm{Co}=6\)
Shape is octahedral.
Oxidation state of Co, \(x+0-1=+2\)
\(\therefore \quad x=+3\)
Electronic configuration of
\(\mathrm{Co}^{3+}=3 d^6=t_{2 \mathrm{~g}}^6 e_{\mathrm{g}}^0\)
\(\begin{gathered}
\mathrm{n}=0 \\
\mu=0
\end{gathered}\)
(iii) \(\mathrm{CrCl}_3(\mathrm{Py})_3\)
IUPAC name is :
trichloridotripyridine chromium (III)
Coordination number of \(\mathrm{Cr}=6\)
Oxidation state of \(\mathrm{Cr}, x-3+0=0\)
\(x=3\)
Electronic configuration of \(\mathrm{Cr}^{3+}=3 d^3=t_{2 \mathrm{~g}}^3 e_{\mathrm{g}}^0\)
Unpaired electrons \((n)=3\)
\(\mu=3.87 \mathrm{BM} .\)
(iv) \(\mathrm{Cs}\left[\mathrm{FeCl}_4\right]\)
IUPAC name is :
cesium tetrachloridoferrate (III)
Coordination number of \(\mathrm{Fe}\) is 4
Shape is tetrahedral
Oxidation number of \(\mathrm{Fe}, x-4=-1\) \(\Rightarrow x=+3\)
Electronic configuration of \(\mathrm{Fe}^{3+}=t_{2 \mathrm{~g}}^3 e_{\mathrm{g}}^2\) \(n=5\)
\(\mu=\sqrt{5(5+2)}=\sqrt{35}=5 \cdot 92 \mathrm{BM}\).
(v) \(\mathrm{K}_4\left[\mathrm{Mn}(\mathrm{CN})_6\right]\)
IUPAC name is :
potassium hexacyanomanganate (II)
Coordination number of \(\mathrm{Mn}=6\)
Shape is octahedral
Oxidation state of \(\mathrm{Mn}\) is \(x-6=-4\)
\(x=+2\)
Electronic configuration of
\(\begin{aligned}
&\mathrm{Mn}^{2+}=3 d^5=t_{2 \mathrm{~g}}^5 e_{\mathrm{g}}^0 \\
&n=1 \\
&\mu=\sqrt{1(1+2)}=\sqrt{3}=1.73 \mathrm{BM} .
\end{aligned}\)