Name the type of isomerism exhibited by the following compounds. Also, draw their corresponding isomers.
(I) \( [\text{Co(NH}_3\text{)}_6][\text{Cr(CN)}_6] \)
(II) \( [\text{Co(en)}_3]^{3+} \)
(III) \( [\text{Co(NH}_3\text{)}_3(\text{NO}_2)_3] \)
(I) The complex \( [\text{Co(NH}_3\text{)}_6][\text{Cr(CN)}_6] \) exhibits ionization isomerism. Ionization isomerism arises when the exchange of ligands between the cationic and anionic parts results in the formation of different ions in solution.
(II) The complex \( [\text{Co(en)}_3]^{3+} \) exhibits linkage isomerism, as the ethylenediamine (en) ligand can bind through different sites.
(III) The complex \( [\text{Co(NH}_3\text{)}_3(\text{NO}_2)_3] \) exhibits geometric isomerism, as the arrangement of ligands around the metal ion can vary.
The metal ions that have the calculated spin only magnetic moment value of 4.9 B.M. are
A. $ Cr^{2+} $
B. $ Fe^{2+} $
C. $ Fe^{3+} $
D. $ Co^{2+} $
E. $ Mn^{2+} $
Choose the correct answer from the options given below