Which of the following is true for the complex `Co(NO_(2) )(Cl)_(2) .5NH_(3)` (Co is in + 3 oxidation state)

Options

A. It shows ionisation isomerism
B. It is inner orbital complex
C. It is diamagnetic
D. All

Answer

To determine which statements are true for the complex \( \text{Co(NO}_2)(\text{Cl})_2 \cdot 5\text{NH}_3 \) where cobalt is in the +3 oxidation state, we can follow these steps:

### Step 1: Identify the oxidation state of cobalt
The oxidation state of cobalt in the complex is given as +3. The nitrite ion (\( \text{NO}_2^- \)) has a charge of -1, and each chloride ion (\( \text{Cl}^- \)) has a charge of -1. The ammonia (\( \text{NH}_3 \)) is a neutral ligand.

### Step 2: Write the overall charge balance
The complex can be represented as:
\[ \text{Co}^{3+} + 2 \text{Cl}^- + 5 \text{NH}_3 + 1 \text{NO}_2^- \]
The total charge from the ligands is:
\[ 2(-1) + 1(-1) = -2 - 1 = -3 \]
Thus, the overall charge is:
\[ +3 - 3 = 0 \]
This confirms the charge balance in the complex.

### Step 3: Determine the coordination number
The coordination number is the total number of ligand donor atoms surrounding the central metal ion. In this case, we have:
- 5 ammonia ligands (each donating 1 pair of electrons)
- 1 nitrite ligand (donating 1 pair of electrons)
- 2 chloride ligands (each donating 1 pair of electrons)

Thus, the coordination number is:
\[ 5 + 1 + 2 = 8 \]

### Step 4: Identify the type of isomerism
The complex can exhibit linkage isomerism due to the presence of nitrite, which can coordinate through either nitrogen or oxygen. It can also show ionization isomerism because the chloride ions can be either inside or outside the coordination sphere.

### Step 5: Determine if the complex is inner or outer orbital
For cobalt in the +3 oxidation state, the electronic configuration is:
\[ \text{Co}^{3+}: [\text{Ar}] 3d^6 \]
In the presence of strong field ligands (like \( \text{NH}_3 \) and \( \text{NO}_2^- \)), the electrons will pair up in the lower energy 3d orbitals. This results in a configuration of \( t_{2g}^6 \) and no unpaired electrons, indicating that the complex is diamagnetic.

### Step 6: Determine the hybridization
With a coordination number of 6, the hybridization is \( d^2sp^3 \), indicating that it is an inner orbital complex.

### Summary of Findings
1. Cobalt is in the +3 oxidation state.
2. The coordination number is 6.
3. The complex can exhibit linkage and ionization isomerism.
4. The complex is an inner orbital complex and is diamagnetic.

### Conclusion
All statements provided in the options regarding the complex \( \text{Co(NO}_2)(\text{Cl})_2 \cdot 5\text{NH}_3 \) are correct.

### Answer
**Option D: All of these.**