Question

A body centre cubic lattice is made up of two different types of atoms A and B. Atom A occupies the body centre and B occupying the corner positions. One of the corners is left unoccupied per, unit cell. Empirical formula of such a solid is:

• A. $AB$
• B. $A_2{B}_3$
• C. $A_5{B}_7$
• D. $A_8{B}_7$

Answer 1

The correct option is D $A_8{B}_7$

There is one $A$ per unit cell

Number of $B$ per unit call $=\frac{1}{8}\times 7=\frac{7}{8}$

empirical formula $=A_1{B}_{7/8}$
$=A_8{B}_7$

Option D is correct.