What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 2/3 of tetrahedral voids ?

Explanation

To find the formula of the compound where element Y forms a cubic close-packed (ccp) lattice and element X occupies 2/3 of the tetrahedral voids, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure**:
- The element Y forms a cubic close-packed (ccp) lattice, which is also known as face-centered cubic (FCC).

2. **Determine the Number of Atoms in the Unit Cell**:
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