Predict the structure of MgO crystal and coordination number of its cation in which the cation and anion radii are equal to 65 pm and 140 pm respectively.

Explanation

To predict the structure of the MgO crystal and the coordination number of its cation, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Cation and Anion Radii**:
- The radius of the cation (Mg²⁺) is given as 65 pm.
- The radius of the anion (O²⁻) is given as 140 pm.

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