• # question_answer In a face centered lattice of X and Y, X atoms are present at the comers while Y atoms are at face centers. Then the formula of the compound is: A)  $X{{Y}_{3}}$                                     B)  ${{X}_{2}}{{Y}_{3}}$   C)  ${{X}_{3}}Y$                         D)  $XY$

for $X,\,8\times \frac{1}{8}\,=1$            For $Y,\,6\times \frac{1}{2}=3$ So $A{{B}_{3}}$