Question

A compound formed by atoms X and Y crystallises in the cubic structure. The atoms X are present at the corners of a cube while atoms Y are at the face-centres. The formula of the compound is ______.

Options

• XY

• X₂Y

• X₃Y

• XY₃

Answer 1

A compound formed by atoms X and Y crystallises in the cubic structure. The atoms X are present at the corners of a cube while atoms Y are at the face-centres. The formula of the compound is XY₃.

Explanation:

Given: Atoms X are at the corners of the cube.

Atoms Y are at the face-centres of the cube.

Y atoms at 6 face centres:

Each face atom is shared by 2 unit cells = `6 × 1/2 = 3` atoms of Y

∴ The formula is XY₃.