Question

In a face centred cubic arrangement of A and B atoms whoso A atoms are at the corner of the unit cell and B atoms at the face centres. One of the B atoms Is missing from one of the faces In the unit cell. The simplest formula of compound is?

• A. $A{B}_3$
• B. $A_8{B}_5$
• C. $A_2{B}_5$
• D. $A{B}_{2/5}$

Answer 1

The correct option is C $A_2{B}_5$

There are 8 A atoms on 8 corner such that $8\times \frac{1}{8}=1A$ in a unit cell.

There are 5B atoms on face centres such that $5\times \frac{1}{2}=\frac{5}{2}B$ atoms in a unit cell.

$\therefore$ The simplest formula is $A_2{B}_5$