Question

The simplest formula of a solid having CCP arrangement for 'A' atoms in which alternate face-centres are occupied by 'B' atoms and alternate edge centres are occupied by 'C' atoms, is?

• A. ABC
• B. $A_8{B}_3{C}_3$
• C. $A_{2}BC$
• D. $A_4{B}_{2}C$

Answer 1

The correct option is B $A_8{B}_3{C}_3$

$Z_{effective}$ of $A=4$ (CCP arrangement)

$Z_{effective}$ of $B=\frac{1}{2}\times \frac{1}{2}\times 6=\frac{3}{2}$ (Alternate face center)

$Z_{effective}$ of $C=\frac{1}{4}\times 12\times \frac{1}{2}=\frac{3}{2}$ (Alternate edges)

Formula:$A_4{B}_{\frac{3}{2}}{C}_{\frac{3}{2}}=A_8{B}_3{C}_3$