9.9 How many geometrical isomers are possible in the following coordination entities?

(i) [Cr(C2O4)3]3–                      (ii) [Co(NH3)3Cl3]

Step 1:

In disubstituted complexes, the substituted groups may be adjacent or opposite to each other. This gives rise to geometric isomerism. It form two isomers cis and trans. 

(i) For [Cr(C2O4)3]3–, no geometric isomer is possible as it is a bidentate ligand. 

(ii) [Co(NH3)3Cl3]

Two geometrical isomers are possible. The structures are as follows: