The optically active species among the following is:

Options

A. `[Cr(NH_(3))_(6)]^(3+)`
B. `[Co(CN)_(6)]^(3-)`
C. `[Co(gly)_(3)]`
D. `[Ru(NH_(3))_(6)]^(3+)`

Answer

To determine the optically active species among the given coordination compounds, we need to analyze the symmetry of each complex. A compound is optically active if it lacks a plane of symmetry (POS) or a center of symmetry (COS). Let's evaluate each option step by step.

### Step 1: Analyze the first complex [Cr(NH3)6]³⁺
- This complex has six identical NH3 ligands arranged in an octahedral geometry.
- Since all ligands are the same, the complex exhibits symmetry.
- It has multiple planes of symmetry, meaning it can be divided into two identical halves.
- **Conclusion**: This complex is optically inactive.

**Hint**: Look for identical ligands in an octahedral complex; they often lead to symmetry.

### Step 2: Analyze the second complex [Co(CN)6]³⁻
- This complex also has six identical CN⁻ ligands in an octahedral arrangement.
- Similar to the first complex, it has symmetry due to identical ligands.
- It possesses a plane of symmetry, thus it is also optically inactive.
- **Conclusion**: This complex is optically inactive.

**Hint**: Identical ligands in octahedral complexes usually indicate optical inactivity.

### Step 3: Analyze the third complex [Co(Gly)3]²⁺
- Glycine (Gly) is a bidentate ligand, coordinating through both the amine (NH2) and carboxylate (COO⁻) groups.
- In this complex, there are three Gly ligands, each contributing two different donor atoms.
- The arrangement of these ligands leads to a structure that lacks symmetry.
- Since the donor atoms are different, the complex does not have a plane of symmetry.
- **Conclusion**: This complex is optically active.

**Hint**: Look for bidentate ligands with different donor atoms; they can create asymmetry.

### Step 4: Analyze the fourth complex [Cr(NH3)6]³⁺ (similar to the first)
- This complex is identical to the first complex, with six NH3 ligands in an octahedral geometry.
- It exhibits symmetry with multiple planes of symmetry.
- **Conclusion**: This complex is optically inactive.

**Hint**: Repeating the analysis for identical complexes will yield the same result regarding optical activity.

### Final Conclusion:
Among the given complexes, the optically active species is **[Co(Gly)3]²⁺**.