Question

9. In the crystal structure of CsCl, the distance between Cs+ and Cl is equal to 3.55 Å (0.355 nm). Calculate density of CsCl (in g/cm3 ).

Answer 1

We know density , d = (Z x atomic mass) / ( No x a³ x 10^-30 cm³ )   

Where Z = No . of atoms in a unit cell = 1                                     Since it is a simple cubic structure   

           atomic mass of CsCl = 168.36 g

           N_o = avagadro number = 6.023x10²³

           a = edge length = 0.355 nm = 0.355x10^-9 m = 355x10^-12 m = 355 pm

Plug the values we get d = (Z x atomic mass) / ( No x a³ x 10^-30 cm³ )   

                                     = (1 x 168.36) / ( 6.023x10²³ x 355³ x 10^-30 cm³ )   

                                    = 6.25 g/cm³

Therefore the density of CsCl is 6.25 g/cm³