Question

A cubic solid is made up of two elements P and Q. Atom Q is present at corners of the cube and atom P at the body centre. What is the formula of the compound? What are the coordination numbers of P and Q ?

Answer 1

Number of Q atoms per unit cell = 1/8 X 8 = 1 Number of P atoms per unit cell = 1x1=1  

Ratio of atoms P : Q = 1:1 Hence, the formula of the compound is PQ.  

As it is a bcc lattice therefore, coordination number is 8 for both P and Q.