Question

In a compound, atoms of element Y form ccp lattice and those of element X occupy `2/3`rd of tetrahedral voids. The formula of the compound will be ______.

Options

• X₄Y₃

• X₂Y₃

• X₂Y

• X₃Y₄

Answer 1

In a compound, atoms of element Y form ccp lattice and those of element X occupy `2/3`rd of tetrahedral voids. The formula of the compound will be X₄Y₃.

Explanation:

Element Y forms a ccp lattice.

Number of Y atoms per unit cell = 1 (as ccp has 4 atoms per unit cell, consider 1 unit for calculation)

Tetrahedral voids = 2 × number of atoms forming ccp

Tetrahedral voids = 2 × 1 = 2

Element X occupies `2/3` of the tetrahedral voids.

X atoms = `2/3 xx 2 = 4/3`

∴ X : Y = `4/3 : 1`   ...(Both sides multiplied by 3)

X : Y = 4 : 3

∴ The formula of the compound will be X₄Y₃.