Question

The correct option(s) regarding the complex $[Co(en)(N{H}_3{)}_3(H_{2}O){]}^{3+}(en=H_{2}NC{H}_{2}C{H}_{2}N{H}_2)$ is (are)

• A. It has two geometrical isomers
• B. It will have three geometrical isomers if bidentate ‘en’ is replaced by two cyanide ligands
• C. It is paramagnetic
• D. It absorbs light at longer wavelength as compared to $[Co(en)(NH3)4{]}^{3+}$

Answer 1

Answer: (A), (B), (D)

(A) $[Co(en)(N{H}_3{)}_3(H_{2}O){]}^{+3}$ complex is type of $[M(AA)b_{3}c]$ have two G.I.
(B) If (en) is replaced by two cynide ligand, complex will be type of $[M{a}_3{b}_{2}c]$ and have 3 G.I.
(C) $[Co(en)(N{H}_3{)}_3(H_{2}O){]}^{3+}$ have d6 configuration $(t_{2g}^6)$ on central metal with SFL therefore it is dimagnetic in nature.
(D) Complex $[Co(en)(N{H}_3{)}_3(H_{2}O){]}^{3+}$ have lesser $CFSE({\Delta }_O)$ value than $[Co(en)(N{H}_3)4{]}^{3+}$ therefore complex $[Co(en)(N{H}_3{)}_3(H_{2}O){]}^{+}$ absorbs longer wavelength for d-d transition.