Given : Atoms of P are present at the bodycentre
Atoms of Q are present at the corners of the cube
To find: Formula of the compound = ?
Co-ordination numbers of P and Q = ?
Calculation: It is given that the atoms of Q are present at the corners of the cube.
∴ Number of atoms contributed by a corner of atom Q per unit cell = 1/8 atoms
Number of atoms contributed by 8 corners of atom Q per unit cell = 1/8 x 8 = 1 atom
It is also given that the atoms of P are present at the body-centre.
Therefore, number of atoms of P in one unit cell = 1 atom This means that the ratio of the number of P atoms to the number of Q atoms, P:Q =1:1
Hence, the formula of the compound is PQ.
The coordination number of both P and Q is 8
