`CsCl` has cubic structure. Its density is `3.99 g cm^(-3)`. What is the distance between `Cs^(o+)` and `Cl^(Θ)` ions?
(Atomic mass of `Cs = 133`)

Explanation

CsCl has BCC struture. It has noe formula unit in the unit cell . So Z=1
` p = ( Z xx M)/ (a^(3) xx N_(0) ) or a^(3) = (Z xx M)/( p xx N_(0)) = (1 xx (133 + 35.5) "g mol" ^(-1))/ (3.99 " g cm"^(-3) xx 6.02 xx 10^(23) " mol" ^(-1)) = 70.15 xx 10^(-24) cm^(3)`
` a = ( 70. 15)^(1//3) xx 10 ^(-8) cm^(3) = ( 70.15) ^(1//3) xx 10^(2) " pm" " " ( 1"pm" =10 ^(-10)" cm")`
` = 4.124 xx 10^(2) " pm" = 412.4 "pm"`
For BCC structure,
Interionic distance (d) ` = (sqrt3a)/2= 1.732/2 xx 412.4 = 357 ` pm (see solved sample problem 2, page 1/34)
( To solve ` (70.15)^(1//3) ` , put ` x = ( 70.15)^(1//3)` , Then ` log x = 1/3 log 70.15 = 1/3 xx 1.8460 = 0.6153`
x = Antilog 0.6153 = 4.124