Question

2) An ionic crystal of AB2 type crystallizes in fluorite style with density 6.45 g/ml. Edge length of unit cell

is 400 Å. If all the ions lying on a body diagonal are removed from all the unit cells then what will be the

new density?​

Answer 1

Answer:

CsCl arranges in body centred type structure

For body centred structures

3

a=2(r

+

+r

−

)

Length of body diagonal =

3

a

⟹7=2(1.69+r

−

)

⟹r

−

=1.81

A

˚