Question

Would you expect the complex [Co(en)₃]Cl₃ to have any unpaired electrons? Any isomers?

a) Yes, unpaired electrons; No isomers
b) No unpaired electrons; No isomers
c) Yes, unpaired electrons; Geometric isomers
d) No unpaired electrons; Geometric isomers

Answer 1

The complex [Co(en)₃]Cl₃ does not have any unpaired electrons, but it exhibits cis-trans isomerism and has an optical isomer.

Step-by-step explanation:

The complex [Co(en)₃]Cl₃ does not have any unpaired electrons. The oxidation state of cobalt (Co) in this complex is +3, which means there are 7 d-electrons. When complexing with en (ethylenediamine), it acts as a strong-field ligand, causing the complex to be low spin. In the low spin configuration, all the d-electrons are paired, resulting in zero unpaired electrons.

This complex does not have any geometric isomers but it has an optical isomer. The [Co(en)₃]Cl₃ complex exhibits cis-trans isomerism. The cis form of the complex exists as a pair of optical isomers, which means that it has a nonsuperimposable mirror image.