Question

A molecule contains atoms $x$ and $y$ so that $x$ occurs at the corners of the cube while $y$ at the face centre. The formula of the molecule can be

• A. $x y _{3}$
• B. $x_{3} y$
• C. $xy _{2}$
• D. $x _{2} y$

Answer 1

Answer: (A)

$x y _{3}$

Answer 2

x atoms are at the corners of the cube, therefore, Number of x-atoms per unit cell $=\frac{1}{8}\times8=1$ y-atoms are at the face centre of cube ? Number of y-atoms per unit cell $=\frac{1}{2}\times6=3$ $\Rightarrow$ The formula of the molecule is xy