Question

binary solid ( A+ B - )has rock salt structure .If the edge length is 400 pm and radius of cation is 75 pm the radius of anion is ............................?

Answer 1

Explanation:

Rock salt has formula Nacl. Nacl has CCP (or) FCC structure.

so, for CCP (or) FCC,

we have,

Radius of cation + Radius of anion = a/2.

let radius of anion is x.

Given radius of cation = 75pm.

Edge length (a) = 400pm.

so, 75+x =400/2.

75+ x = 200.

x= 200_75

x= 125 pm.

Radius of anion (x) = 125 pm.