Question

Two elements P and Q have B.C.C. and F.C.C. structures . What will be the no. of tetrahedral and and octahedral voids per unit cell..?​

Answer 1

P will have 2 octahedral and 4 tetrahedral voids whereas Q will have 4 octahedral and 8 tetrahedral voids.

- No of octahedral voids = N

- No of tetrahedral voids = 2N

(where N is the no of atoms per unit cell)

- For BCC, N = 2

⇒ No of octahedral voids in P = 2

⇒ No of tetrahedral voids in P = 4

- For FCC, N = 4

⇒ No of octahedral voids in Q = 4

⇒ No of tetrahedral voids in Q = 8