$\begin{array}{1 1}(A)\;A_6B_{23}&(B)\;A_7B_{27}\\(C)\;A_7B_{24}&(D)\;A_6B_{24}\end{array} $

Number of atoms of A at the corners = 7 (because one A is missing)

$\therefore$ Contribution atoms of A towards unit cell=$7\times \large\frac{1}{8}=\frac{7}{8}$

Number of atoms B at face-centres = 6

$\therefore$ Contribution of atom B towards unit cell =$6\times \large\frac{1}{2}$$=3$

Ratio of A : B =$\large\frac{7}{8} $$: 3=7 : 24$

$\therefore$ Formula is $A_7B_{24}$

Hence (C) is the correct answer.

Ask Question

Tag:MathPhyChemBioOther

Take Test

...