Question

Specify whether the following complexes have isomers.

\(\begin{aligned}{}(a)tetrahedral\left( {Ni{{(CO)}_2}{{(Cl)}_2}} \right)\\(b)trigonalbipyramidal\left( {Mn{{(CO)}_4}NO} \right)\\(c)\left( {Pt{{(en)}_2}C{l_2}} \right)C{l_2}\end{aligned}\)

Short answer

Isomers are the chemical species which have the same molecular formula but different arrangement of atoms or ligands in space. Space isomerism is of two type namely geometrical and optical isomerism.

Step-by-step solution

Step  1: Explanation

(a)

• For\(\left( {{\rm{Ni}}{{({\rm{CO}})}_2}{\rm{C}}{{\rm{l}}_2}} \right)\),We can see that central metal atom \({\rm{Ni}}\)is attached to \(2\) molecules of \({\rm{CO}}\)and \(2{\rm{C}}{{\rm{l}}^ - }\)ions in tetrahedral arrangement.
• All tetrahedral positions are equivalent and molecule contains a plane of symmetry, which specifies that this molecule will not show geometrical or optical isomerism.

(b)

• For\(\left( {{\rm{Mn}}{{({\rm{CO}})}_4}{\rm{NO}}} \right)\),We can see that central metal atom \({\rm{Mn}}\)is attached to \(4\) molecules of \({\rm{CO}}\)and \(1{\rm{NO}}\)in trigonal bipyramidal arrangement. NO group can be present at equatorial or axial position.
• As this molecule cannot have mirror images, it means this molecule will not show geometrical or optical isomerism.

(c)

• For\(\left( {{\rm{Pt}}{{({\rm{en}})}_2}{\rm{C}}{{\rm{l}}_2}} \right){\rm{Cl}}{l_2}\), We can see that central metal atom \(Pt\)is attached to \(2\) molecules of ethylene diamine, which is a bidentate ligand, and \(2{\rm{C}}{{\rm{l}}^ - }\)ions.
• This means this molecule will have cis and trans isomers. Also, cis isomers will show optical isomerism, but, trans will not as it contains a plane of symmetry.

Result

a) It does not have isomers.

b) It does not have isomers.

c) It has cis and trans isomers, in which cis isomers are optical isomers.