Q76P - Chemistry: Molecular Nature Of Matter And Change

Question

For any of the following that can exist as isomers, state the type of isomerism and draw the structures:

[CO(NH₃)₅Cl]Br₂ 

[Pt(CH₃NH₂)₃Cl]Br 

[Fe(H₂O)(NH₃)₂] ²⁺

Step-by-Step Solution

Answer

The 3 chemical structures given in the questions show isomerism. They exist as geometric (cis-trans) isomers and coordination isomers. 

 

[CO(NH₃)₅Cl]Br₂ - coordination isomerism

[Pt(CH₃NH₂)₃Cl]Br -coordination isomerism 

[Fe(H₂O)(NH₃)₂]²⁺ -Geometric (cis-trans) isomerism  

 

Step 1: Concept Used – Isomerism

Definition of different kinds of isomers

 

1. Constitutional (structural) isomers - same formula, differently connected atoms; they can occur in two types:

 

1. Coordination isomers - they occur when the structure of the whole compound is the same, but the structure of complex ion is different

 

1. Linkage isomers - they occur when the structure of the complex ion is the    same, but the donor atom that which ligand uses is different

 

1. Stereoisomers - they have the same connections between atoms, but the atoms have different spatial arrangements; they occur in two types:

 

1. geometric (cis-trans) isomers - different spatial arrangements of atoms or groups, relative to the central metal ion.

 

          2.2    Optical isomers - they occur when a molecule cannot be superimposed with its mirror image.

Step 2: Elucidation of type of isomerism and structure

[CO(NH₃)₅Cl]Br₂ - coordination isomerism

it can be [CO(NH₃)₅Cl]Br₂ or [CO(NH₃)₅Br]BrCl

Step 3: Elucidation of type of isomerism and structure

[Pt(CH₃NH₂)₃Cl]Br - coordination isomerism

it can be [Pt(CH₃NH₂)₃Br]Cl or [Pt(CH₃NH₂)₃Cl]Br 

Step 4: Elucidation of type of isomerism and structure

[Fe(H₂O)₄(NH₃)₂]²⁺- Geometric (cis-trans) isomerism