Which of the following complexes show geometrical as well as optical isomerism ?
(i) `[Cr(o x)_(3)]^(3-)`
(ii) `[Rh (e n)_(2)Cl_(2)]^(+)`
(iii) `[Co(NH_(3))_(2)Cl_(2)(e n)]^(+)`
Select the correct code

Options

A. (i) only
B. (i) & (ii) only
C. (ii) & (iii) only
D. (i), (ii), & (iii)

Answer

To determine which of the given complexes exhibit both geometrical and optical isomerism, we will analyze each complex step by step.

### Step 1: Analyze the first complex `[Cr(o x)_(3)]^(3-)`
- The complex contains three bidentate oxalate ligands (ox).
- The coordination number of chromium is 6, which typically leads to an octahedral geometry.
- In an octahedral complex with three bidentate ligands, the arrangement can lead to geometrical isomerism (cis and trans forms).
- However, due to the symmetry of the oxalate ligands, this complex does not have non-superimposable mirror images, meaning it does not exhibit optical isomerism.

**Hint:** Check the symmetry of the ligands and their arrangement to determine if optical isomers can exist.

### Step 2: Analyze the second complex `[Rh(e n)_(2)Cl_(2)]^(+)`
- This complex has two bidentate ethylenediamine (en) ligands and two chloride ligands.
- The coordination number is 6, leading to an octahedral geometry.
- The arrangement can be cis or trans. The cis form can lead to geometrical isomerism.
- The cis form can also have non-superimposable mirror images, indicating that it can exhibit optical isomerism.

**Hint:** Consider the arrangement of the ligands and whether they can create non-superimposable mirror images.

### Step 3: Analyze the third complex `[Co(NH_(3))_(2)Cl_(2)(e n)]^(+)`
- This complex has two ammonia (NH3) ligands, two chloride (Cl) ligands, and one bidentate ethylenediamine (en) ligand.
- The coordination number is also 6, leading to an octahedral geometry.
- The arrangement can be cis or trans, leading to geometrical isomerism.
- The cis form can also have non-superimposable mirror images, indicating that it can exhibit optical isomerism.

**Hint:** Look for the presence of bidentate ligands and their arrangement to determine the possibility of optical isomerism.

### Conclusion
- The first complex `[Cr(o x)_(3)]^(3-)` does not exhibit geometrical or optical isomerism.
- The second complex `[Rh(e n)_(2)Cl_(2)]^(+)` exhibits both geometrical and optical isomerism.
- The third complex `[Co(NH_(3))_(2)Cl_(2)(e n)]^(+)` also exhibits both geometrical and optical isomerism.

Thus, the complexes that show geometrical as well as optical isomerism are the second and third complexes.

**Final Answer:** The correct code is (ii) and (iii).