Which of the following is high spin complex ?

Options

A. `[CoCl_(6)]^(3-)`
B. `[FeF_(6)]^(3-)`
C. `[Co(NH_(3))_(6)]^(2+)`
D. All of these

Explanation

To determine which of the following complexes is a high spin complex, we need to analyze the ligands and their field strength. High spin complexes are typically formed with weak field ligands, while low spin complexes are formed with strong field ligands.

### Step-by-Step Solution:

1. **Identify the Complexes**: We need to look at the given complexes and identify their ligands. The complexes mentioned in the video are:
- CoCl6^3-
- FeF6^3-
- Co(NH3)6^2+

2. **Determine the Oxidation State**:
- For CoCl6^3-:
- Chloride (Cl) has a charge of -1.
- Let the oxidation state of cobalt (Co) be x.
- The equation becomes: x + 6(-1) = -3 → x - 6 = -3 → x = +3.
- For FeF6^3-:
- Fluoride (F) has a charge of -1.
- Let the oxidation state of iron (Fe) be y.
- The equation becomes: y + 6(-1) = -3 → y - 6 = -3 → y = +3.
- For Co(NH3)6^2+:
- Ammonia (NH3) is a neutral ligand (0 charge).
- Let the oxidation state of cobalt (Co) be z.
- The equation becomes: z + 6(0) = +2 → z = +2.

3. **Identify the Ligand Field Strength**:
- Chloride (Cl-) is a weak field ligand.
- Fluoride (F-) is also a weak field ligand.
- Ammonia (NH3) is generally considered a strong field ligand, but in some cases, it can behave as a weak field ligand depending on the metal center and its oxidation state.

4. **Determine Spin State**:
- CoCl6^3-: Since Cl- is a weak field ligand, this complex will be a high spin complex.
- FeF6^3-: Since F- is also a weak field ligand, this complex will also be a high spin complex.
- Co(NH3)6^2+: Although NH3 is generally a strong field ligand, in this case with Co(II), it can be considered a weak field ligand, leading to a high spin configuration.

5. **Conclusion**: All three complexes (CoCl6^3-, FeF6^3-, and Co(NH3)6^2+) are high spin complexes. Therefore, the answer is that all of these complexes are high spin complexes.

### Final Answer:
All of the above complexes are high spin complexes (Option 4).