Give the total number of possible isomers of
`[Co1_(2)(CN)(NH_(3))en]` .

Explanation

To determine the total number of possible isomers for the complex `[Co(NH3)2(CN)(en)]`, we will analyze the coordination compound step by step.

### Step 1: Identify the Coordination Number and Geometry
The given complex contains cobalt (Co) as the central metal ion, and it is coordinated to four ligands: two ammonia (NH3) molecules, one cyanide (CN), and one ethylenediamine (en). Since cobalt typically exhibits an octahedral geometry in coordination complexes, we can conclude that this complex will also have an octahedral geometry.

**Hint:** Identify the central metal ion and its coordination number based on the ligands attached.

### Step 2: Classify the Ligands
In this complex:
- NH3 is a monodentate ligand (binds through one donor atom).
- CN is a monodentate ligand (binds through one donor atom).
- en (ethylenediamine) is a bidentate ligand (binds through two donor atoms).

**Hint:** Classify the ligands as monodentate or bidentate to understand their binding behavior.

### Step 3: Determine Possible Geometric Isomers
For octahedral complexes, geometric isomers can be classified as cis and trans:
- **Cis Isomer**: The two NH3 ligands can be adjacent to each other.
- **Trans Isomer**: The two NH3 ligands can be opposite each other.

Given that we have one bidentate ligand (en), it can also affect the arrangement of the ligands.

**Hint:** Visualize the arrangement of ligands in octahedral geometry to determine possible cis and trans configurations.

### Step 4: Consider Optical Isomers
Cis isomers can exhibit optical isomerism if they are non-superimposable mirror images. In this case, the cis configuration with two NH3 ligands adjacent to each other can lead to optical isomers.

**Hint:** Check if the arrangement of ligands allows for non-superimposable mirror images, indicating optical isomerism.

### Step 5: Consider Ambidentate Ligands
The cyanide (CN) ligand can exist in two forms: as cyanide (CN) or isocyanide (NC). This introduces additional isomers since the ligand can bind through different atoms.

**Hint:** Identify if any ligands can exist in more than one binding form, which can lead to additional isomers.

### Step 6: Calculate Total Isomers
1. **Cis Isomers**:
- 1 cis with CN as CN and 1 cis with CN as NC (2 isomers).
- Each of these can have optical isomers (2 optical isomers).

Total for cis = 2 (from CN and NC) × 2 (optical) = 4.

2. **Trans Isomers**:
- 1 trans with CN as CN and 1 trans with CN as NC (2 isomers).
- Trans does not have optical isomers.

Total for trans = 2.

3. **Total Isomers** = 4 (cis) + 2 (trans) = 6.

### Final Answer
The total number of possible isomers of the complex `[Co(NH3)2(CN)(en)]` is **6**.

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