Question

The density of CaF2, fluorite structure) A 3 18 cm'. The
length of the side of the unit cell is
(a) 253 pm (b) 344 pm ( 546 pm (d) 273 pm​

Answer 1

Answer:

CaF2 = Ca2+ (in fcc structure) + F– (at tetrahedral void) = 4 + 8 = 12 atoms = 4 molecules

Answer 2

Answer:c)546 pm

Explanation:

For CaF2 z=4 m=78

d=318 cc. Na=6.022*10^23

We know that

d=Zm/a^3.Na

a3=Zm/d Na

A3=4*78/318*10^3 **6.022*10^23

a3=16.2*10^23

a=546 pm