Chapter 9, Problem 9C.19E

Interpretation Introduction

Interpretation:

The possible isomers for the complex ${\left[\text{Co}\left(\text{en}\right)\text{3}\right]}^{\text{3+}}$ have to be given.

Concept Introduction:

Isomers:

The compounds with same molecular formula but differ in the arrangement of the atom are said to be isomers.

Linkage isomers:

Linkage isomerism occurs with ambidentate ligands that are capable of coordinating in more than one way.

Example:

${\text{SCN}}^{\text{-}}{\text{/NCS}}^{\text{-}}$.  The only difference is the atoms bind to the central ion.  The ligand must have more than one donor atom but bind to ion in only one place.

Hydrate Isomers:

Hydrate isomers results from replacement of a coordinated group by a solvent molecule in this case it is a water molecule.

Coordination Isomers:

Coordination isomerism arises in compounds containing complex anionic and cationic parts.  Hence, there are two complex compounds bound together, one with a negative charge and the other with a positive charge.  In coordination isomers, the anion and cation complexes of a coordination compound exchange one or more ligands.

Ionization Isomers:

Ionization isomers occur when a ligand is bound to the metal center exchanges places with an anion or neutral molecule that was previously outside the coordination complex.

Geometrical isomers:

If there is restricted rotation in a molecule there arises geometric isomerism.  Geometric isomers are also known as Cis- trans isomerism.

• If the two atoms locked in same side of the molecule then it is called as cis isomers.
• If the two atoms locked in opposite side of the molecule then it is called as trans isomers.