Question

What type of isomerism is exhibited by the following pairs of compounds :
(i) $\left[Pt{Cl}_2{\left(N{H}_3\right)}_4\right]{Br}_2$ and $\left[Pt{Br}_2{\left(N{H}_3\right)}_4\right]{Cl}_2$
(ii) ${\left[Cr\left(SCN\right){\left(H_{2}O\right)}_5\right]}^{2+}$ and ${\left[Cr\left(NCS\right){\left(H_{2}O\right)}_5\right]}^{2+}$

Answer 1

(i) $\left[Pt{Cl}_2{\left(N{H}_3\right)}_4\right]{Br}_2$ and $\left[Pt{Br}_2{\left(N{H}_3\right)}_4\right]{Cl}_2$ are ionization isomers.
In ionization isomerism, there is an exchange of ions inside and outside the coordination sphere. Ionisation isomers have same formula but produce different isomers in solution.
(ii) ${\left[Cr\left(SCN\right){\left(H_{2}O\right)}_5\right]}^{2+}$ and ${\left[Cr\left(NCS\right){\left(H_{2}O\right)}_5\right]}^{2+}$ are linkage isomers.
In linkage isomerism, the same ligand is bonded to central metal atom or ion through different atoms. Linkage isomers have the same molecular formula but differ in the linkage of the ligand to central metal atom.