In a close packed structure of mixed oxide, the lattice is composed of `O^(2-)` ions. One eighth of tetrahedral voids are occupied by divalent cations `A^(2+)` and one half of octahedral voids by trivalent cations `B^(3+)` What is the formula of oxide ? 

Explanation

To determine the formula of the mixed oxide in a close-packed structure composed of oxide ions (O²⁻), we will follow these steps:

### Step 1: Determine the number of oxide ions
Let the number of O²⁻ ions in the lattice be represented as \( n \).

### Step 2: Calculate the number of tetrahedral and octahedral voids
In a close-packed structure:
- The number of tetrahedral voids is \( 2n \) (twice the number of O²⁻ ions).
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