What is the formula of the compound in which the element Y forms CCP lattice and atoms of X occupy two third of tetrahedral voids?

To determine the formula of the compound where element Y forms a cubic close-packed (CCP) lattice and element X occupies two-thirds of the tetrahedral voids, we can follow these steps:

Understanding the Lattice Structure

In a CCP lattice, there are a total of 8 tetrahedral voids for every unit cell. Since element X occupies two-thirds of these voids, we can calculate the number of occupied voids:

• Total tetrahedral voids = 8
• Occupied tetrahedral voids = (2/3) * 8 = 5.33 (approximately 5)

Counting Atoms in the Unit Cell

In a CCP lattice, there are 4 atoms of Y per unit cell. Therefore, we have:

• Atoms of Y = 4
• Atoms of X = 5 (from the occupied tetrahedral voids)

Formulating the Compound

Now, we can express the ratio of Y to X in the compound:

• Y : X = 4 : 5

Final Formula

The empirical formula of the compound can be represented as:

This indicates that for every 4 atoms of Y, there are 5 atoms of X in the compound.