Both potassium ferrocyanide and potassium ferricyanide are diamagnetic .

Explanation

To determine whether both potassium ferrocyanide and potassium ferricyanide are diamagnetic, we need to analyze the oxidation states of iron in each compound and their respective electron configurations.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Potassium Ferrocyanide: K₄[Fe(CN)₆]
- Potassium Ferricyanide: K₃[Fe(CN)₆]

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