Which of the following is the high spin complex?

Options

A. `[Cr(gly)_(3)]`
B. `[CoBr_(2)CI_(2)(SCN)_(2)]^(3-)`
C. `[Fe(CN)_(6)]^(3-)`
D. `Na[PtBrCI(NO_(2))_(2)(NH_(3))_(2)]`

Answer

To determine which of the following complexes is a high spin complex, we need to analyze the number of unpaired electrons in each complex. A high spin complex typically has more unpaired electrons due to weaker field ligands that do not cause pairing of electrons in the d-orbitals.

### Step-by-Step Solution:

1. **Identify the complexes**: We have four complexes to analyze:
- 1) Chromium with glycinate
- 2) Cobalt with bromide, chloride, and thiocyanate
- 3) Iron with cyanide
- 4) Platinum with bromide, chloride, nitro, and ammonia

2. **Calculate the oxidation state of the metal in each complex**:
- **Chromium with glycinate**:
- Glycinate is a neutral ligand.
- Oxidation state of Cr = +3 (since it is not given, we assume it is +3).
- **Cobalt with Br2, Cl2, and SCN**:
- Oxidation state of Co = +3 (considering the charges of the ligands).
- **Iron with CN**:
- Oxidation state of Fe = +3 (since CN is a strong field ligand).
- **Platinum with Br, Cl, NO2, and NH3**:
- Oxidation state of Pt = +3 (considering the charges of the ligands).

3. **Determine the electronic configuration of each metal ion**:
- **Chromium (Cr^3+)**:
- Configuration: [Ar] 3d³ (3 unpaired electrons).
- **Cobalt (Co^3+)**:
- Configuration: [Ar] 3d⁶ (4 unpaired electrons, as it is a weak field ligand).
- **Iron (Fe^3+)**:
- Configuration: [Ar] 3d⁵ (1 unpaired electron due to strong field ligand causing pairing).
- **Platinum (Pt^3+)**:
- Configuration: [Xe] 5d⁷ (3 unpaired electrons).

4. **Count the number of unpaired electrons**:
- **Chromium**: 3 unpaired electrons.
- **Cobalt**: 4 unpaired electrons.
- **Iron**: 1 unpaired electron.
- **Platinum**: 3 unpaired electrons.

5. **Identify the high spin complex**:
- The complex with the highest number of unpaired electrons is the cobalt complex, which has 4 unpaired electrons. This indicates that it is a high spin complex.

### Conclusion:
The high spin complex among the given options is the cobalt complex (option B).

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