Question

6.
In the CsCl structure
= 1.37. The side length of the unit cell in terms of ris:
(A) a= 2r-
(B) a=r
(C) a = 1.414r
(D) a=4r-

Answer 1

Answer:

age equals to 2 - is the correct answer

Answer 2

Concept:

A cube having an edge length has a body diagonal of √3a.

Given:

In the  CsCl structure, r⁻/r⁺ = 1.37.

Find:

The side length of the unit cell in terms of r⁻, the radius of the anion.

Solution:

In the CsCl structure, anions form a simple cubic lattice. Here, anions occupy the corners of the cubic unit cell and the cations occupy the cubical void present in the body center.

In a body-centered cubic (BCC) structure cations and anions are touching each other along the body diagonal.

Body diagonal = 2 ( r⁻ + r⁺ ) = √3a

2 ( r⁻ + r⁻/1.37) = √3a

2r⁻ (1 + 1/1.37) = √3a

1.73 × 2r⁻ = 1.73 a

Hence, 2r⁻ = a

Hence, 2r⁻ = a and the correct option is (a) a =  2r⁻.

#SPJ2