The number of possible isomers for the complex `[Co(C_(2)O_(4))(NH_(3))_(2)]` is

Options

A. 1
B. 2
C. 3
D. 4

Answer

To determine the number of possible isomers for the complex \([Co(C_2O_4)(NH_3)_2]\), we need to analyze the coordination environment of the cobalt ion in this octahedral complex.

### Step-by-Step Solution:

1. **Identify the Coordination Number and Geometry**:
- The complex has cobalt (Co) as the central metal ion. The ligands present are oxalate \((C_2O_4^{2-})\) and ammonia \((NH_3)\).
- The coordination number of cobalt in this complex is 6, which indicates an octahedral geometry.

2. **Determine the Types of Ligands**:
- The oxalate ion is a bidentate ligand, meaning it can bond to the metal at two sites. Ammonia is a monodentate ligand, bonding at one site.
- In total, we have 1 bidentate ligand (oxalate) and 2 monodentate ligands (ammonia).

3. **Identify Possible Isomer Configurations**:
- In an octahedral complex with the given ligands, we can have different arrangements of the ligands.
- The oxalate can occupy two coordination sites, and the ammonia can occupy the remaining four sites.

4. **Cis and Trans Isomers**:
- For the arrangement of the ligands, we can have:
- **Cis Isomers**: Where the two ammonia ligands are adjacent to each other.
- **Trans Isomers**: Where the two ammonia ligands are opposite each other.
- Since the oxalate is bidentate, it will occupy two adjacent positions, leading to two distinct cis configurations and two distinct trans configurations.

5. **Optical Isomerism**:
- The cis isomers can exhibit optical isomerism due to the arrangement of the ligands around the cobalt ion. This means that each cis configuration can have a non-superimposable mirror image.
- Therefore, we have 2 cis isomers (each having a pair of enantiomers) and 2 trans isomers.

6. **Total Count of Isomers**:
- Thus, the total number of isomers is:
- 2 cis isomers (each with 1 pair of enantiomers) = 2
- 2 trans isomers = 2
- Total = 2 (cis) + 2 (trans) = 4 isomers.

### Final Answer:
The number of possible isomers for the complex \([Co(C_2O_4)(NH_3)_2]\) is **4**.