Question

A crystal is formed by two elements X and Y in cubic structure. X atoms are at the corners of a cube while Y atoms are at the face centre. The formula of the compound will be

• A. XY
• B. $XY_{2}$
• C. $X_{2}Y_{3}$
• D. $XY_{3}$

Answer 1

(d) No. of X atom (at the corners) $= \frac{1}{8} \times 8 = 1$

NO. of Y atoms (fcc)

$= 6 \times \frac{1}{2} = 3$

Hence, the formula is $XY_{3}.$